Recording method and apparatus, and editing method apparatus

ABSTRACT

A recording method includes the steps of causing a first management system retained in a first apparatus to manage a storage medium loaded in a second apparatus when the first apparatus and the second apparatus are connected to one another; and recording the data to the storage medium based on a second management system which is retained in the second apparatus and which limits consecution of data recording segments when it is determined that data transferred from the first apparatus to the second apparatus are to be recorded to the storage medium. A recording apparatus and editing method and apparatus also manage data storage and editing between first and second apparatuses.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a recording method andapparatus, and editing method and apparatus for functionally expanding amagneto-optical disc usable by a conventional mini-disc (MD) system, theexpansion being made in such a manner as to maintain compatibility withthe conventional MD system.

2. Discussion of the Background

The so-called Mini-disc (MD), a 64 mm-across magneto-optical disc housedin a cartridge, has gained widespread acceptance today as a storagemedium to and from which digital audio data are recorded and reproduced.

The MD system adopts ATRAC (Adaptive TRansform Acoustic Coding) as itsaudio data compression method. ATRAC involves compression-coding audiodata by what is called MDCT (Modified Discrete Cosine Transform). Theaudio data has been acquired through a predetermined time window.Typically, music data are compressed by ATRAC to one-fifth to one-tenththe original size.

The MD system utilizes a convolution code called ACIRC (Advanced CrossInterleave Reed-Solomon Code) as its error correction system and EFM(Eight-to-Fourteen Modulation) as its modulation technique. ACIRC is aconvolution code that provides dual error correction on C1 and C2sequences (in vertical and oblique directions). The method is used tocarry out a powerful error correction process on sequential data such asaudio data. One disadvantage of ACIRC is that it requires a linkingsector arrangement for data update purposes. ACIRC and EFM are basicallythe same as those employed in a conventional compact disc (CD) system.

For music data management, the MD system uses U-TOC (User TOC [Table ofContents]). Specifically, a U-TOC area is furnished on an inner side ofa recordable area of the disc. For the current MD system, U-TOCconstitutes the track (audio track/data track) title sequence andmanagement information that is updated to keep up with the recording ordeletion of such tracks. Under the U-TOC scheme, each track (i.e., partsconstituting each track) is managed in terms of start position, endposition, and mode settings.

The disc for the MD system is small, inexpensive, and offers goodcharacteristics when used by the system to record or reproduce audiodata. These advantages have enabled the MD system to gain widespreadmarket acceptance.

As recognized by the present inventors, MD systems have not fullyachieved their potential in the market as they are not compatible withgeneral purpose computers, such as personal computers. Moreover,conventional MD systems use different file management schemes than theFile Allocation Table (FAT)-based file systems used in personalcomputers.

With more general use of personal computers and PC-based networking,more and more audio data are distributed over PC-based networks. Today,it is common practice for the user of a personal computer to use it asan audio server from which to download favorite music files to aportable data reproducing apparatus for music reproduction. Asrecognized by the present inventors, because the conventional MD systemis not fully compatible with personal computers, a new MD system isdesirable that would adopt a general-purpose management system, such asa FAT (File Allocation Table) system, to enhance PC-compatibility.

As explained in White, R., “How Computers Work, Millennium Edition” QueCorporation, pages 146 and 158 for example, 1999, the entire contents ofwhich being incorporated herein by reference, the FAT is created by thedisk drive on a particular disk sector, such as sector 0. The term “FAT”(or “FAT System”) is used generically herein to describe variousPC-based file systems, and is intended to cover the specific FAT-basedfile systems used in DOS, VFAT (virtual FAT) used in Windows 95/98, FAT32 used in Windows 98/ME/2000, as well as NTFS (NT file system;sometimes New Technology File System) which is the file system used byWindows NT operating system, or optionally in Windows 2000 operatingsystem, for storing and retrieving files on read/write disks. NTFS isthe Windows NT equivalent of the Windows 95 file allocation table (FAT)and the OS/2 High Performance File System (HPFS).

Meanwhile, a higher degree of compatibility with personal computersmeans increased risk of unauthorized copying of copyrighted works, whichin-turn requires better techniques to protect against unauthorizedcopying of audio works. One technological way of reinforcing copyrightlaws involves encrypting the audio works when recorded. It is alsodesired that music titles and artist names recorded on the disc bemanaged in a more efficient manner than at present.

The current MD system uses a disc with a storage capacity of about 160MB, which, as recognized by the present inventors, is not alwayssufficient for the user's requirement for data storage. It is thusdesired that the storage capacity of a new disc be boosted whileremaining backwards-compatible with the current MD system.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to overcome the aboveand other deficiencies of the related art and to provide a reproducingmethod, reproducing apparatus, a recording method, and recordingapparatus for efficiently managing audio data through the integration ofthe FAT system on MD media. Alternatively, other media formats be usedas well in light of the teachings of the present disclosure.

While a “summary” of selected aspects of the invention are providedbelow, this summary is not intended to be an exhaustive listing of allnovel attributes and combination of attributes of the present invention.Nor is this summary intended to be construed independent of the otheraspects of the present disclosure.

In carrying out the invention and according to one aspect thereof, thereis provided a recording method including the steps of causing a firstmanagement system retained in a first apparatus to manage a storagemedium loaded in a second apparatus when the first apparatus and thesecond apparatus are connected to one another; and recording the data tothe storage medium based on a second management system which is retainedin the second apparatus and which limits consecution of data recordingsegments when it is determined that data transferred from the firstapparatus to the second apparatus are to be recorded to the storagemedium.

A feature of the first aspect of the present invention is that itfurther includes the step of recording the data to the storage mediumunder the second management system based on a write request commandtransferred from the first apparatus to the second apparatus.

Another feature of the first aspect of the present invention is that itfurther includes the steps of executing software instructions stored ina storing means within the first apparatus so as to output the writerequest command to record audio data stored in the storing means to thestorage medium in response to a user-actuated instruction; transferringthe write request command from the first apparatus to the secondapparatus; reading-out the audio data from the storing means; executingother software instructions so as to compress the audio data and outputcompressed audio data; transferring the compressed audio data from thefirst apparatus to the second apparatus; and recording at the secondapparatus the compressed audio data to the storage medium under thesecond management system according to the write request command.

Still another feature of the first aspect of the present invention isthat it further includes the steps of searching for free areas having atleast a predetermined physical length based on the second managementsystem configured to manage a file stored in the storage medium;generating a track descriptor having an attribute of a track and anencryption key configured to encrypt the compressed audio data to bestored in the storage medium; generating a part descriptor having a partpointer information pointing to the file; recording as encryptedcompressed audio data the compressed audio data encrypted with theencryption key in the free areas; connecting the free areas where theencrypted compressed audio data is recorded to an end of the filemanaged by the second management system under the second managementsystem; recording the part pointer information pointing to the freeareas where the encrypted compressed audio data is recorded in the partdescriptor; recording a decryption key so as to enable later decryptionof the encrypted compressed audio data and pointer information pointingto the part descriptor in the track descriptor; and recording a tracknumber that points to the track descriptor in a play order table havinga play order of a plurality of tracks.

A feature of the first aspect of the present invention is that thesecond management system is configured to search consecutive free areashaving at least a physical length of 64 kilobytes multiplied by four.

A second aspect of the present invention is directed to a recordingmethod in a recording apparatus, includes the steps of causing a firstmanagement system retained in an another apparatus to manage a storagemedium loaded in the recording apparatus when the recording apparatusand the another apparatus are connected; and recording the data to thestorage medium based on a second management system which is retained inthe recording apparatus and which limits concatenation of data recordingsegments when data transferred from the another apparatus to therecording apparatus are to be recorded to the storage medium.

A third aspect of the present invention is directed to an editing methodthat includes the steps of causing a first management system retained inthe first apparatus to manage a storage medium loaded in the secondapparatus when a first apparatus and a second apparatus are connected;and deleting the part of the file based on a second management systemwhich is retained in the second apparatus when the first apparatusinstructs part of a file to be deleted from the storage medium loaded inthe second apparatus.

A feature of the third aspect of the present invention is that itfurther includes the steps of obtaining track information correspondingto a predetermined track from a play order table having a plurality oftrack information that respectively point to a track descriptor in atrack information table; obtaining a track descriptor designated by thetrack information from the track information table, the track descriptorincluding a decryption key corresponding to a track and pointerinformation that points to one of a plurality of part descriptors in apart information table; reading a part descriptor corresponding to thepointer information in the track descriptor; reading a part of the fileaccording to part pointer information in the part descriptor, the partpointer information pointing to the part of the file; and decryptingwith the decryption key the part of the file.

Another feature of the third aspect of the present invention is that itfurther includes the steps of transferring at least the track descriptorfrom the second apparatus to the first apparatus; transferring a deleterequest command and a track identification to be deleted from the firstapparatus to the second apparatus; obtaining track informationcorresponding to the track to be deleted from a play order table;obtaining a track descriptor designated by the track information from atrack information table; adjusting a play order of a track set to beplayed after the track to be deleted; reading the part descriptorcorresponding to the pointer information in the track descriptor;separating a data block as the part of the file specified by the partpointer information in the part descriptor from the file on the secondmanagement system and freeing the data block on the second managementsystem; freeing the part descriptor on the file system; and freeing thetrack descriptor on the file system.

A fourth aspect of the present invention is directed to an editingmethod in an editing apparatus that includes the steps of causing afirst management system retained in the another apparatus to manage astorage medium loaded in the editing apparatus when the editingapparatus and an another apparatus are connected to one another; anddeleting the part of the file based on a second management system thatis retained in the editing apparatus when the another apparatusinstructs part of a file to be deleted from the storage medium loaded inthe editing apparatus.

According to this invention, a track information file and an audio datafile are generated on a disc serving as the storage medium. These arethe files managed by the so-called FAT system.

The audio data file is a file that accommodates a plurality of audiodata items. When viewed from the FAT system, the audio data file appearsto be a very large file. The composition of this file is divided intoparts, so that audio data are handled as a set of such parts.

The track information file is a file that describes various types ofinformation for managing the audio data contained in the audio datafile. The track index file is made up of a play order table, aprogrammed play order table, a group information table, a trackinformation table, a part information table, and a name table.

The play order table indicates the order of audio data reproductiondefined by default. As such, the play order table contains informationrepresenting links to track descriptors corresponding to track numbers(i.e., music title numbers) in the track information table.

The programmed play order table contains the order of audio datareproduction defined by the individual user. As such, the programmedplay order table describes programmed track information representinglinks to the track descriptors corresponding to the track numbers.

The group information table describes information about groups. A groupis defined as a set of one or more tracks having serial track numbers,or a set of one or more tracks with programmed serial track numbers.

The track information table describes information about tracksrepresenting music titles. Specifically, the track information table ismade up of track descriptors representing tracks (music titles). Eachtrack descriptor describes a coding system, copyright managementinformation, content decryption key information, pointer informationpointing to the part number serving as the entry to the music title ofthe track in question, an artist name, a title name, original titleorder information, and recording time information about the track inquestion.

The part information table describes pointers allowing part numbers topoint to actual music title locations. Specifically, the partinformation table is made up of part descriptors corresponding toindividual parts. Entries of part descriptors are designated from thetrack information table. Each part descriptor is composed of a startaddress and an end address of the J part in question in the audio datafile, and a link to the next part.

When audio data are desired to be reproduced from a particular track,information about the designated track number is retrieved from the playorder table. The track descriptor corresponding to the track from whichto reproduce the audio data is then acquired.

Key information is then obtained from the applicable track descriptor inthe track information table, and the part descriptor indicating the areacontaining entry data is acquired. From the part descriptor, access isgained to the location, in the audio data file, of the first partcontaining the desired audio data, and data are retrieved from theaccessed location. The reproduced data from the location are decryptedusing the acquired key information for audio data reproduction. If thepart descriptor has a link to another part, the linked part is accessedand the above steps are repeated.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects of the invention will be seen by reference tothe description, taken in connection with the accompanying drawing, inwhich:

FIG. 1 is an explanatory view of a disc for use with a next-generationMD1 system ;

FIG. 2 is an explanatory view of a recordable area on the disc for usewith the next-generation MD1 system ;

FIGS. 3A and 3B are explanatory views of a disc for use with anext-generation MD2 system;

FIG. 4 is an explanatory view of a recordable area on the disc for usewith the next-generation MD2 system;

FIG. 5 is an explanatory view of an error-correcting code scheme for usewith the next-generation MD1 and MD2 systems;

FIG. 6 is another explanatory view of the error-correcting code schemefor use with the next-generation MD1 and MD2 systems;

FIG. 7 is another explanatory view of the error-correcting code schemefor use with the next-generation MD1 and MD2 systems;

FIG. 8 is a perspective view of a disc portion showing how an addresssignal is generated using wobbles;

FIG. 9 is an explanatory view of an ADIP signal for use with the currentMD system and the next-generation MD1 system ;

FIG. 10 is another explanatory view of the ADIP signal for use with thecurrent MD system and the next-generation MD1 system ;

FIG. 11 is an explanatory view of an ADIP signal for use with thenext-generation MD2 system;

FIG. 12 is another explanatory view of the ADIP signal for use with thenext-generation MD2 system;

FIG. 13 is a schematic view showing relations between the ADIP signaland frames for the current MD system and the next-generation MD1 system;

FIG. 14 is a schematic view indicating relations between the ADIP signaland frames for the next-generation MD1 system ;

FIG. 15 is an explanatory view of a control signal for use with thenext-generation MD2 system;

FIG. 16 is a block diagram of a disc drive unit;

FIG. 17 is a block diagram of a media drive unit;

FIG. 18 is a flowchart of steps for initializing a next-generation MD1disc;

FIG. 19 is a flowchart of steps for initializing a next-generation MD2disc;

FIG. 20 is an explanatory view of a signal recording bitmap;

FIG. 21 is a flowchart of steps for reading data from a FAT sector;

FIG. 22 is a flowchart of steps for writing data to a FAT sector;

FIG. 23 is a flowchart of steps in which the disc drive unit alone readsdata from a FAT sector;

FIG. 24 is a flowchart of steps in which the disc drive unit alonewrites data to a FAT sector;

FIG. 25 is a flowchart of steps for generating a signal recordingbitmap;

FIG. 26 is another flowchart of steps for generating the signalrecording bitmap;

FIG. 27 is another flowchart of steps for generating the signalrecording bitmap;

FIG. 28 is an explanatory view of a first example of an audio datamanagement system;

FIG. 29 an explanatory view of an audio data file for use with the firstexample of the audio data management system;

FIG. 30 is an explanatory view of a track index file for use with thefirst example of the audio data management system;

FIG. 31 is an explanatory view of a play order table for use with thefirst example of the audio data management system;

FIG. 32 is an explanatory view of a programmed play order table for usewith the first example of the audio data management system;

FIGS. 33A and 33B are explanatory views of a group information table foruse with the first example of the audio data management system;

FIGS. 34A and 34B are explanatory views of a track information table foruse with the first example of the audio data management system;

FIGS. 35A and 35B are explanatory views of a part information table foruse with the first example of the audio data management system;

FIGS. 36A and 36B are explanatory views of a name table for use with thefirst example of the audio data management system;

FIG. 37 is an explanatory view of typical processing performed by thefirst example of the audio data management system;

FIG. 38 is an explanatory view showing how each name slot in the nametable is accessed from a plurality of pointers;

FIGS. 39A and 39B are explanatory views of a process performed by thefirst example of the audio data management system to delete parts fromthe audio data file;

FIG. 40 is an explanatory view of a second example of the audio datamanagement system;

FIG. 41 an explanatory view of an audio data file for use with thesecond example of the audio data management system;

FIG. 42 is an explanatory view of a track index file for use with thesecond example of the audio data management system;

FIG. 43 is an explanatory view of a play order table for use with thesecond example of the audio data management system;

FIG. 44 is an explanatory view of a programmed play order table for usewith the second example of the audio data management system;

FIGS. 45A and 45B are explanatory views of a group information table foruse with the second example of the audio data management system;

FIGS. 46A and 46B are explanatory views of a track information table foruse with the second example of the audio data management system;

FIGS. 47A and 47B are explanatory views of a name table for use with thesecond example of the audio data management system;

FIG. 48 is an explanatory view of typical processing performed by thesecond example of the audio data management system;

FIG. 49 is an explanatory view showing how the second example of theaudio data management system divides one file data item into a pluralityof indexed areas using an index scheme;

FIG. 50 is an explanatory view depicting how the second example of theaudio data management system connects tracks using the index scheme;

FIG. 51 is an explanatory view indicating how the second example of theaudio data management system connects tracks using another scheme;

FIGS. 52A and 52B are explanatory views sketching how managementauthority is moved between a personal computer and a disc drive unitconnected therewith depending on the type of data to be written to adisc loaded in the drive unit;

FIGS. 53A, 53B, and 53C are explanatory views illustrating an audio datacheck-out procedure;

FIG. 54 is a schematic view portraying conceptually how thenext-generation MD1 system and the current MD system may coexist in thedisc drive unit;

FIG. 55 is an external view of a portable disc drive unit;

FIG. 56 is a flowchart of steps carried out by the disc drive unit informatting a disc loaded therein;

FIG. 57 is a flowchart of steps carried out by the disc drive unit informatting a virgin disc loaded therein;

FIG. 58 is a flowchart of steps carried out by the disc drive unit inrecording audio data to a disc loaded therein; and

FIG. 59 is a flowchart of steps for switching from the disc format ofthe next-generation MD1 system to the disc format of the current MDsystem.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description is divided into the following 10 sections:

-   -   1. Outline of the recording system    -   2. Discs    -   3. Signal formats    -   4. Structure of the recording/reproducing apparatus    -   5. Initialization of next-generation MD1 and MD2 discs    -   6. First example of the audio data management system    -   7. Second example of the audio data management system    -   8. Operation during connection with the personal computer    -   9. Restrictions on copying of audio data from the disc    -   10. Coexistence of the next-generation MD1 system with the        current MD system    -   1. Outline of the Recording System

The recording/reproducing apparatus according to the present inventionuses a magneto-optical disc as its storage medium. The physicalattributes, such as form-factor, of the disc are substantially similarto the disc utilized by so-called MD (Mini-disc) systems. However, datarecorded on the disc and how the data is arranged on the disc differsfrom a conventional MD. More particularly, the inventive apparatusemploys a FAT (File Allocation Table) system as its file managementsystem for recording or reproducing content data such as audio data, sothat compatibility with existing personal computers is ensured. Onceagain, the term “FAT” (or “FAT System”) is used generically herein todescribe various PC-based file systems, and it intended to bedescriptive of the specific FAT structure used in DOS, VFAT (virtualFAT) used in Windows 95/98, FAT 32 used in Windows 98/ME/2000, as wellas NTFS (NT file system; sometimes New Technology File System) which isthe file system used by Windows NT operating system, or optionally inWindows 2000 operating system, for storing and retrieving files on aread/write disks. Compared with the conventional MD system, therecording/reproducing apparatus of the invention has an improved errorcorrection system and an advanced modulation technique designed to boostdata storage capacity and to increase data security. Furthermore, theinventive apparatus encrypts content data and takes measures to preventillegal data copying and ensure copyright protection for the contentdata.

Generally, there are two kinds of specifications, MD1 and MD2, developedby the present inventors for the next-generation MD system. The MD1specifications involve the use of the same disc (i.e., physical medium)as that which is currently used by the existing MD system. The MD2specifications adopt a disc which has a same form-factor as, and isidentical externally to the disc of the current MD system, but whichutilizes a magnetic super-resolution (MSR) technique to enhancerecording density in the linear direction, whereby storage capacity isboosted.

The current MD system utilizes as its storage medium a 64 mm-acrossmagneto-optical disc enclosed in a cartridge. The disc is 1.2 mm thickand has a center hole 11 mm in diameter. The cartridge measures 68 mm by72 mm by 5 mm.

The dimensions and shapes of the discs and cartridges are the same asthe next-generation MD1 and MD2 systems. On both the MD1 and MD2 discs,the start position of the lead-in area is the same as with the currentMD system, i.e., starting at 29 mm.

It is proposed for the next-generation MD2 system that the track pitchbe in an inclusive range of 1.2 μm through 1.3 μm (e.g., 1.25 μm). Forthe next-generation MD1 system with its disc structurally identical tothat of the current MD system, the track pitch is set to 1.6 μm. The bitlength is set to 0.44 μm/bit for the next-generation MD1 disc andproposed at 0.16 μm/bit for the MD2 disc. Redundancy is set to 20.50%for both the next-generation MD1 and the next-generation MD2 discs.

The next-generation MD2 disc is arranged to increase its storagecapacity in the linear direction by resorting to the magneticsuper-resolution technique. The MSR technique involves taking advantageof a specific phenomenon on the disc: that a cut-through layer becomesmagnetically neutral when a particular temperature is reached, allowingmagnetic walls that were transferred to a regenerative layer to move insuch a manner that infinitesimal markings are viewed apparently largerunder a beam spot.

That is, the next-generation MD2 disc is constituted by a magnetic layeracting as a recording layer for recording at least data, by acut-through layer, and by a magnetic layer for data regeneration, alldeposited on a transparent substrate. The cut-through layer serves as alayer that regulates switched connective force. When a specifictemperature is reached, the cut-through layer becomes magneticallyneutral to let the magnetic walls transferred in the recording layer beshifted into the regenerative magnetic layer. This allows infinitesimalmarkings to become visible under the beam spot. For data recording, alaser pulse magnetic field modulation technique is adopted to generateminuscule markings on the disc.

On the next-generation MD2 disc, grooves are made deeper than with aconventional MD disc and their gradient is steeper as well so as toimprove de-track margins and to reduce land-induced crosstalk, wobblesignal crosstalk, and focus leaks. Illustratively, the grooves are in aninclusive range of 160 nm through 180 nm deep, the groove gradient is inan inclusive range of 60 through 70 degrees, and the groove width is inan inclusive range of 600 nm through 700 nm on the next-generation MD2disc.

As part of its optical specifications, the next-generation MD1 disc hasits laser wavelength λ set to 780 nm and its numerical aperture NA to0.45 for an objective lens in an optical head. Likewise, thenext-generation MD2 disc has its laser wavelength λ also set to 780 nmand its numerical aperture NA to 0.45 for the objective lens in theoptical head.

The next-generation MD1 and MD2 systems both adopt the so-called grooverecording system as their recording scheme. That is, grooves are formedover the disc surface as tracks for recording and reproduction purposes.

As its error-correcting code system, the existing MD system utilizes aconvolutional code based on ACIRC (Advanced Cross InterleaveReed-Solomon Code). By contract, the next-generation MD1 and MD2 systemsemploy a block complete code that combines RS-LDC (Reed Solomon-LongDistance Code) with BIS (Burst Indicator Subcode). Using the blockcomplete error-correcting code eliminates the need for linking sectors.Under the error correction scheme combining LDC with BIS, the locationof a burst error that may occur is detected by BIS. The error locationis utilized in getting the LDC code to effect erasure correction.

Adopted as the addressing system is the so-called wobbled groove systemwhereby a single spiral groove is formed, and both sides of the grooveare flanked by wobbles furnished as address information. This type ofaddressing system is called ADIP (Address in Pregroove). The current MDsystem and the next-generation MD1 and MD2 systems differ in lineardensity. Whereas the current MD system adopts as its error-correctingcode a convolutional code called ACIRC, the next-generation MD1 and MD2systems are set to use the block complete code combining LDC and BIS. Asa result, the current MD system and the next-generation MD1 and MD2systems differ in redundancy and have different relative positionsbetween ADIP and data. For these reasons, the next-generation MD1 systemwith its physical disc structurally identical to that of the current MDsystem handles the ADIP signal in a manner different from the current MDsystem. The next-generation MD2 system is set to modify its ADIP signalspecifications for better compliance with the next-generation MD2specifications.

The current MD system adopts EFM (8 to 14 modulation) as its modulationsystem, whereas the next-generation MD1 and MD2 systems utilize RLL(1,7)PP (RLL, Run Length Parity Preserve/Prohibit rmtr [repeated minimumtransition Limited; PP, runlength]), called the 1-7 pp modulation systemhereinafter. The next-generation MD1 and MD2 systems use a Viterbidecoding method as their data detection method, based on partialresponse PR(1, 2, 1)ML for the MD1 system and on partial response PR(1,−1)ML for the MD2 system.

The disc driving system adopts either CLV (Constant Linear Velocity) orZCAV (Zone Constant Angular Velocity). Standard linear velocity is setto 2.4 m/sec for the next-generation MD1 system and 1.98 m/sec for thenext-generation MD2 system. With the current MD system, standard linearvelocity is set to 1.2 m/sec for 60-min discs and 1.4 m/sec for 74-mindiscs.

For the next generation MD1 system with its disc structurally identicalto that of the current MD system, total data storage capacity per discis about 300 megabytes (on the 80-min disc). Because the 1-7 ppmodulation system is adopted instead of EFM as the modulation system,window margins are changed from 0.5 to 0.666, whereby recording densityis increased by a factor of 1.33. Since the ACIRC system is replaced bythe combination of BIS with LDC as the error correction system, dataefficiency is boosted, whereby recording density is further increased bya factor of 1.48. Overall, with the same disc in use, data storagecapacity is made approximately double that of the current MD system.

The next-generation MD2 disc utilizing the magnetic super-resolutiontechnique is further boosted in recording density in the lineardirection; the total data storage capacity amounts to about onegigabytes.

At standard linear velocity, the data rate is set to 4.4 megabits/secfor the next-generation MD1 system and 9.8 megabits/sec for thenext-generation MD2 system.

2. Discs

FIG. 1 shows a typical structure of the next-generation MD1 disc. Thisdisc is structurally identical to that of the current MD system. Thatis, the disc is made up of a dielectric film, a magnetic film, anotherdielectric film, and a reflective film, deposited on a transparentpolycarbonate substrate. The disc surface is covered with a protectivefilm.

On the next-generation MD1 disc, as shown in FIG. 1, a lead-in area onthe innermost side (of the recordable area, where “innermost” refers toa radial direction relative to a center of the disc) has a P-TOC(Pre-mastered TOC [Table Of Contents]) area. As a physical structure,this area constitutes a pre-mastered area. That is, embossed pits areformed here to record control information and other related informationsuch as P-TOC information.

On the outer side, in the radial direction, of the lead-in areaincluding the P-TOC area is a recordable area (where magneto-opticalrecording is possible). This is a recordable as well as reproduciblearea including recording tracks furnished with grooves as their guides.On the inner side of the recordable area is a U-TOC (User TOC) area.

The U-TOC area is the same in structure as that of the current MD systemin which disc management information is recorded. What is held in theU-TOC area is the order of track (audio track/data track) titles andmanagement information written over as needed to keep up with therecording or erasure of such tracks. More specifically, the managementinformation includes start and end positions of tracks (i.e., partsmaking up the tracks) and mode settings.

An alert track is furnished on the outer side of the U-TOC area. Thistrack contains an alert sound recorded thereon that is activated(audibilized) by the MD player if the disc is loaded into the current MDsystem. The sound indicates a warning that the disc is for use with thenext-generation MD1 system and cannot be used for reproduction with thecurrent system. The remaining portion of the recordable area (shown inmore detail in FIG. 2) is followed in the radial direction by a lead-outarea.

FIG. 2 shows a typical structure of the recordable area on thenext-generation MD1 disc indicated in FIG. 1. As illustrated in FIG. 2,the beginning of the recordable area (inner side) has the U-TOC area andthe alert track. A region containing the U-TOC area and alert track hasits data recorded in EFM format so that the data may be reproduced bycurrent MD system players. On the outer side of the area of data storedin EFM format is an area where data are recorded in 1-7 pp modulationformat for the next-generation MD1 system . There is a clearance of apredetermined distance called a “guard band” between the area of datarecordings in EFM format on the one hand, and the area of data storagein 1-7 pp modulation format on the other hand. The guard band isintended to prevent malfunction of the current MD player when the latteris loaded with a next-generation MD1 system disc.

At the beginning of the area of data recordings in 1-7 pp modulationformat (i.e., inner side), there are a DDT (Disc Description Table) areaand a reserve track. The DDT area is designed to replace physicallydefective regions and includes a unique ID (UID). The UID is unique toeach storage medium, typically based on randomly generated numbers. Thereserve track is provided to accommodate information for contentprotection.

Furthermore, the area of data storage in 1-7 pp modulation formatincludes a FAT (File Allocation Table) area. The FAT area is an areathat allows the FAT system to manage data pursuant to FAT systemcriteria used by general-purpose computers. More specifically, the FATsystem carries out file management based on FAT chains involving both adirectory indicating the entry points of root files and directories, anda FAT table describing FAT cluster link information. Once again, theterm FAT is used in a general sense to refer to a variety of differentfile management schemes employed by PC operating systems.

The U-TOC area on the next-generation MD1 disc records two kinds ofinformation: an alert track start position, and the start position ofthe area for data storage in 1-7 pp modulation format.

When a next-generation MD1 disc is loaded into a current MD systemplayer, information is read from the U-TOC area of the loaded disc. Theretrieved U-TOC information reveals the alert track position, allowingthe alert track to be accessed so that its data will start beingreproduced. The alert track contains data constituting the alert soundwarning that the disc is for the next-generation MD1 system and cannotbe used for reproduction with the current system.

The alert sound may illustratively articulate a message like “This disccannot be used on this player.” Alternatively, the alert sound may alsobe a simple beep, tone or other warning signal.

When a next-generation MD1 disc is loaded into a next-generation MD1system player, information is read from the U-TOC area of the loadeddisc. The retrieved U-TOC information reveals the start position of thearea where data are stored in 1-7 pp modulation format and allows datato be read from the DDT, reserve track, and FAT area. Over the area ofdata storage in 1-7 pp modulation format, data management is effectednot with the U-TOC but with the FAT system.

FIGS. 3A and 3B show a typical structure of the next-generation MD2disc. This disc is also made up of a dielectric film, a magnetic film,another dielectric film, and a reflective film, deposited on atransparent polycarbonate substrate. The disc surface is covered with aprotective film.

On the next-generation MD2 disc, as depicted in FIG. 3A, the lead-inarea on the inner side (in a radial direction) has control informationrecorded using an ADIP signal. On the MD2 disc, the currently-used P-TOCarea of embossed pits is replaced by the lead-in area having controlinformation based on the ADIP signal. The recordable area starting fromoutside the lead-in area is a recordable as well as reproducible areathat has grooves formed therein as guides for recording tracks. Therecordable area has data recorded in 1-7 pp modulation format.

On the next-generation MD2 disc, as indicated in FIG. 3B, the magneticfilm is constituted by a magnetic layer 101 acting as a recording layerfor recording data, by a cut-through layer 102, and by a magnetic layer103 for data regeneration, all deposited on the substrate. Thecut-through layer 102 serves as a layer that regulates switchedconnective force. When a specific temperature is reached, thecut-through layer 102 becomes magnetically neutral to let the magneticwalls transferred in the recording layer 101 to be shifted into theregenerative magnetic layer 103. This allows infinitesimal markings inthe recording layer 101 to be viewed as apparently enlarged under thebeam spot on the regenerative magnetic layer 103.

Whether a loaded disc is a next-generation MD1 disc or a next-generationMD2 disc can be determined based on the information retrieved from thelead-in area. Specifically, if P-TOC information in embossed pits isdetected from the lead-in area, it means the loaded disc is a current MDsystem disc or a next-generation MD1 disc. If control information basedon the ADIP signal is detected from the lead-in area, with no P-TOCinformation in embossed pits detected, it means the disc in question isa next-generation MD2 disc. However, this manner of distinguishing theMD1 disc from the MD2 disc is not limitative of the invention.Alternatively, phase differences in a tracking error signal betweenon-track and off-track modes may be utilized in determining the disctype. As another alternative, the disc may be given a detection hole fordisc identification purposes.

FIG. 4 shows a typical structure of the recordable area on thenext-generation MD2 disc. As illustrated in FIG. 4, the recordable areahas all its data recorded in 1-7 pp modulation format. A DDT area and areserve track are located at the beginning of (i.e., on the inner sideof) the area where data are recorded in 1-7 pp modulation format. TheDDT area is provided to record alternate area management data formanaging alternate areas intended to replace physically defective areas.Moreover, the DDT area includes a management table that manages areplacement area, which includes a recordable area that substitutes forthe physically defective areas. The management table keeps track of thelogical cluster(s) determined to be defective and also keeps tracks ofthe logical cluster(s) in the replacement area assigned to replace thedefective logical clusters. The DDT area also contains the UID mentionedabove. The reserve track stores information for content protectionpurposes.

A FAT area is also included in the area with its data recorded in 1-7 ppmodulation format. The FAT area is used by the FAT system for managingdata. The FAT system, in this embodiment, effects data managementpursuant to the FAT system criteria applicable to general-purposepersonal computers.

No U-TOC area is provided on the next-generation MD2 disc. When anext-generation MD2 disc is loaded into a next-generation MD2 player,data are read from the DDT area, reserve track, and FAT located asdescribed above on the disc. The retrieved data are used for datamanagement by the FAT system.

A time-consuming initialization process is not needed on next-generationMD1 and MD2 discs. More specifically, initialization is not required onthese discs except for advance preparation of a DDT area, a reservetrack, and a minimum set of tables including a FAT table. Data may bedirectly written to the recordable area of an unused disc and then readtherefrom without recourse to an initialization process.

3. Signal Formats

What follows is a description of signal formats for the next-generationMD1 and MD2 systems. The current MD system utilizes the convolutionalcode called ACIRC as its error correction system in which a 2,352-bytesector corresponding to the data size of a sub-code block is regarded asan increment of access for read and write operations. Because theconvolutional code scheme involves an error-correcting code sequencespanning a plurality of sectors, it is necessary to provide a linkingsector between adjacent sectors when data are to be updated. As itsaddressing system, the current MD system adopts the wobbled groovescheme called ADIP in which a single spiral groove is formed, and bothsides of the groove are flanked by wobbles furnished as addressinformation. The current MD system optimally arranges the ADIP signalfor gaining access to the 2,352-byte sector.

The next-generation MD1 and MD2 systems, by contrast, employ a blockcomplete code scheme that combines LDC with BIS, and regards a64-kilobyte block as an increment of access for read and writeoperations. Linking sectors are not needed by the block complete code.This, however, requires that the next-generation MD1 system utilizingthe disc of the current MD system rearrange the ADIP signal in a mannercomplying with a new recording method. The next-generation MD2 system isset to alter the ADIP signal specifications to comply with thespecifications of the next-generation MD2 system.

FIGS. 5, 6, and 7 are explanatory views of the error correction systemfor use with the next-generation MD1 and MD2 systems. This errorcorrection system combines an LDC-based error-correcting code schemeillustrated in FIG. 5, with the BIS scheme shown in FIGS. 6 and 7.

FIG. 5 depicts a typical structure of a code block in the LDC-basederror-correcting code scheme. As shown in FIG. 5, each error-correctingcode sector is provided with a four-byte error detection code EDC, anddata are laid out two-dimensionally in the error-correcting code blockthat is 304 bytes long horizontally and 216 bytes long vertically. Eacherror-correcting code sector is made up of two-kilobyte data. Asillustrated in FIG. 5, the 304-byte-by-216-byte error-correcting codeblock includes 32 error-correcting code sectors of two-kilobyte dataeach. The 32 error-correcting code sectors laid out two-dimensionally inthe 304-byte-by-216-byte error-correcting code block are furnishedvertically with a 32bit error-correcting Reed-Solomon parity code.

FIGS. 6 and 7 depict a typical BIS structure. As shown in FIG. 6, aone-byte BIS is inserted at intervals of 38 bytes of data. One frame isconstituted by 152 bytes (38×4) of data, three-byte BIS data, and2.5-byte frame sync data amounting to 157.5 bytes of data.

As shown in FIG. 7, a BIS block is formed by 496 frames each structuredas described above. A BIS data code (3×496=1,488 bytes) includes576-byte user control data, a 144-byte address unit number, and a768-byte error-correcting code.

As described, the BIS code has the 768-byte error-correcting codeattached to the 1,488-byte data. This code structure provides areinforced error correction feature. With this BIS code embedded atintervals of 38 bytes of data, the location of any error that may occuris readily detected. The error location is then used as the basis forerasure correction using the LDC code.

The ADIP signal is recorded as wobbles formed on both sides of a singlespiral groove, as shown in FIG. 8. That is, the ADIP signal is recordedby having address data frequency-modulated and formed into groovewobbles in disc material.

FIG. 9 depicts a typical sector format of the ADIP signal for thenext-generation MD1 system.

As shown in FIG. 9, each sector of the ADIP signal (ADIP sector) is madeup of four-bit sync data, eight high-order bits of an ADIP clusternumber, eight low-order bits of the ADIP cluster number, an eight-bitADIP sector number, and a 14-bit error detection code CRC.

The sync data constitute a signal of a predetermined pattern used todetect the beginning of an ADIP sector. Linking sectors are needed bythe current MD system, because this system utilizes convolutionalcoding. The sector numbers for linking use are negative numbers forsectors FCh, FDh, FEh, and FFh (h: hexadecimal). The ADIP sector formatis the same as that of the current MD system, because thenext-generation MD1 system utilizes the same disc used by the current MDsystem.

The next-generation MD1 system , as shown in FIG. 10, has its ADPcluster structure formed by 36 ADIP sectors ranging from FCh to FFh andfrom 0Fh to 1Fh. And as illustrated in FIG. 10, one ADIP cluster is madeup of data constituting two recording blocks of 64 kilobytes each.

FIG. 11 depicts an ADIP sector structure for use with thenext-generation MD2 system. This structure contains 16 ADIP sectors, sothat each ADIP sector number can be expressed in four bits. Linkingsectors are not needed by the next-generation MD2 system, because thesystem uses the block complete error-correcting code.

As shown in FIG. 11, the ADIP sector structure for the next-generationMD2 system includes four-bit sync data, four high-order bits of an ADIPcluster number, eight mid-order bits of the ADIP cluster number, fourlow-order bits of the ADIP cluster number, a four-bit ADIP sectornumber, and an 18-bit error-correcting parity code.

The sync data constitute a signal of a predetermined pattern used todetect the beginning of an ADIP sector. The ADIP cluster numberconstitutes 16 bites, i.e., high-order four bits, mid-order eight bits,and low-order four bits. Since 16 ADIP sectors make up an ADIP cluster,each ADIP sector number is given in four bits. Whereas the current MDsystem utilizes the 14-bit error-detecting code, the next-generation MD2system employs the 18-bit error-correcting parity code. For thenext-generation MD2 system, as show in FIG. 12, each ADIP cluster isprovided with one recording block of 64 kilobytes.

FIG. 13 depicts relations between an ADIP cluster and BIS frames for thenext-generation MD1 system .

As shown in FIG. 10, one ADIP cluster is constituted by 36 ADIP sectorsranging from FC to FF and from 00 to 1F. A recording block of 64kilobytes, which is an increment for read and write operations, is laidout in two portions in each ADIP cluster.

Each ADIP sector is divided into two parts, i.e., the first-half 18sectors and the second-half 18 sectors as shown in FIG. 13.

The data in one recording block forming an increment for read and writeoperations are placed in a BIS block made of 496 frames ranging fromframe 10 to frame 505. The 496-frame data constituting the BIS block areprefixed with a 10-frame preamble ranging from frame 0 to frame 9. Thedata frames are further suffixed with a six-frame postamble ranging fromframe 506 to frame 511. A total of 512 frames of data are thus placed ineach of the first and the second half of the ADIP cluster, the firsthalf ranging from ADIP sector FCh to ADIP sector 0Dh, the second halfranging from ADIP sector 0Eh to ADIP sector 1Fh. The preamble andpostamble are provided to protect the data upon linkage with adjacentrecording blocks. The preamble frames are also used for data PLLsettlement, signal amplitude control, and signal offset control.

A physical address used to record or reproduce data to or from a givenrecording block is designated in two portions: an ADIP cluster, anddistinction of either the first half or the second half of the cluster.When a physical address is designated for a write or a read operation,the ADIP sector is first read from the ADIP signal in question. From areproduced signal of the ADIP sector, the ADIP cluster number and ADIPsector number are retrieved so as to determine whether the first half orthe second half of the ADIP cluster is in effect.

FIG. 14 illustrates relations between an ADIP cluster and BIS frames forthe next-generation MD2 system. For the next-generation MD2 system, asshown in FIG. 12, 16 ADIP sectors constitute one ADIP cluster. Each ADIPcluster is furnished with one recording block of 64 kilobytes of data.

As shown in FIG. 14, the data in one recording block (64 kilobytes)constituting an increment for read and write operations are placed in aBIS block made up of 496 frames ranging from frame 10 to frame 505. The496-frame data constituting the BIS block are prefixed with a 10-framepreamble ranging from frame 0 to frame 9. The data frames are furthersuffixed with a six-frame postamble ranging from frame 506 to frame 511.A total of 512 frames of data are placed in the ADIP cluster rangingfrom ADIP sector 0h to ADIP sector Fh.

The preamble and postamble frames before and after the data frames areprovided to protect the data upon linkage with adjacent recordingblocks. The preamble frames are also used for data PLL settlement,signal amplitude control, and signal offset control.

A physical address used to record or reproduce data to or from a givenrecording block is designated in the form of an ADIP cluster. When aphysical address is designated for a write or a read operation, the ADIPsector is first read from the ADIP signal in question. From a reproducedsignal of the ADIP sector, the ADIP cluster number is then retrieved.

To start writing or reading data to or from the disc of the abovestructure requires using various kinds of control information for laserpower calibration and other purposes. As shown in FIG. 1, thenext-generation MD1 disc has the P-TOC area included in the lead-inarea. Diverse items of control information are acquired from the P-TOCarea.

A P-TOC area in embossed pits is not provided on the next-generation MD2disc; control information is instead recorded using the ADIP signal inthe lead-in area. Because the next-generation MD2 disc utilizes themagnetic super-resolution technique, laser power control is an importantfactor. For that reason, calibration areas for use in power control areprovided in the lead-in and lead-out areas of the next-generation MD2disc.

FIG. 15 shows a lead-in/lead-out area structure on the next-generationMD2 disc. As illustrated in FIG. 15, the lead-in and lead-out areas ofthe disc have each a power calibration area for laser beam power controlpurposes.

The lead-in area includes a control area that records ADIP controlinformation. The ADIP control information describes disc control datausing the low-order bit area of the ADIP cluster number.

More specifically, the ADIP cluster number starts at the beginning ofthe recordable area and constitutes a negative value in the lead-inarea. As shown in FIG. 15, the ADIP sector on the next-generation MD2disc is made up of four-bit sync data, eight high-order bits of the ADIPcluster number, eight-bit control data (i.e., low-order bits of the ADIPcluster number), a four-bit ADIP sector number, and an 18-biterror-correcting parity code. As depicted in FIG. 15, the eightlow-order bits of the ADIP cluster number describe control data such asa disc type, magnetic phase, intensity, and read power.

The high-order bits of the ADIP cluster number are left intact, whichpermits detection of the current cluster position with a fairly highdegree of accuracy. ADIP sector “0” and ADIP sector “8” allow thelocations of ADIP clusters to be known precisely at predeterminedintervals, because the eight low-order bits of the ADIP cluster numberare left intact.

How control data are recorded using the ADIP signal is described indetail in Applicants' Japanese Patent Application No. 2001-123535, filedin the Japanese Patent Office in 2001, the entire contents of whichbeing incorporated herein by reference.

4. Structure of the Recording/Reproducing Apparatus

Described below with reference to FIGS. 16 and 17 is a typical structureof a disc drive unit (recording/reproducing apparatus) that complieswith discs for recording/reproducing use with the next-generation MD1and MD2 systems.

FIG. 16 shows a disc drive unit 1 that is connectable illustrativelywith a personal computer 100.

The disc drive unit 1 includes a media drive unit 2, a memory transfercontroller 3, a cluster buffer memory 4, an auxiliary memory 5, USB(Universal Serial Bus) interfaces 6 and 8, a USB hub 7, a systemcontroller 9, and an audio processing unit 10.

The media drive unit 2 permits recording and reproduction of data to andfrom a loaded disc 90. The disc 90 is a next-generation MD1 disc, anext-generation MD2 disc, or a current MD system disc. An internalstructure of the media drive unit 2 will be discussed later withreference to FIG. 17.

The memory transfer controller 3 controls transfers of write and readdata to and from the media drive unit 2.

Under control of the memory transfer controller 3, the cluster buffermemory 4 buffers data that are read in increments of recording blocksfrom data tracks of the disc 90 by the media drive unit 2.

The auxiliary memory 5, under control of the memory transfer controller3, stores various items of management information and specialinformation retrieved from the disc 90 by the media drive unit 2.

The system controller 9 provides overall control inside the disc driveunit 1. Furthermore, the system controller 9 controls communicationswith the personal computer 100 connected to the disc drive unit 1.

More specifically, the system controller 9 is communicatively connectedto the personal computer 100 via the USB interface 8 and USB hub 7. Inthis setup, the system controller 9 receives commands such as a writerequest and a read request from the personal computer 100 and transmitsstatus information and other necessary information to the PC 100.

Illustratively, when the disc 90 is loaded into the media drive unit 2,the system controller 9 instructs the media drive unit 2 to retrievemanagement information and others from the disc 90, and causes thememory transfer controller 3 to place the retrieved managementinformation, etc., into the auxiliary memory 5.

Given a request from the personal computer 100 for reading a certain FATsector, the system controller 9 causes the media drive unit 2 to read arecording block containing the FAT sector in question. The retrievedrecording block data are written to the cluster buffer memory 4 undercontrol of the memory transfer controller 3.

From the recording block data written in the cluster buffer memory 4,the system controller 9 retrieves the data constituting the requestedFAT sector. The retrieved data are transmitted to the personal computer100 through the USB interface 6 and USB hub 7 under control of thesystem controller 9.

Given a request from the personal computer 100 for writing a certain FATsector, the system controller 9 causes the media drive unit 2 to readthe recording block containing the FAT sector in question. The retrievedrecording block is written to the cluster buffer memory 4 under controlof the memory transfer controller 3.

The system controller 9 feeds the memory transfer controller 3 with theFAT sector data (i.e., write data) coming from the personal computer 100via the USB interface 6. In the cluster buffer memory 4, thecorresponding FAT sector data are updated under control of the systemcontroller 9.

The system controller 9 then instructs the memory transfer controller 3to transfer from the cluster buffer memory 4 the recording block data,with the relevant FAT sector updated therein, to the media drive unit 2as write data. The media drive unit 2 writes the received recordingblock data to the disc 90 following a data modulation process.

A switch 50 is connected to the system controller 9. This switch 50 isused to set the operation mode of the disc drive unit 1 to either thenext-generation MD1 system or the current MD system. In other words, thedisc drive unit 1 is capable of writing audio data to the current MDsystem disc 90 in one of two formats: in the format of the current MDsystem, or in the format of the next-generation MD1 system . The switch50 serves to show the user explicitly what operation mode is set on thedisc drive unit 1. While a mechanical switch is shown, an electrical,magnetic or hybrid switch may be used as well.

The disc drive unit 1 is furnished with a display unit 51 such as an LCD(Liquid Crystal Display). When fed with a display control signal fromthe system controller 9, the display unit 51 may display text data andsimplified icons constituting status information on the disc drive unit1 as well as user-oriented messages.

In its input section, the audio processing unit 10 includesillustratively an analog audio signal input part made of a line inputcircuit and a microphone input circuit, an A/D converter, and a digitalaudio data input part. The audio processing unit 10 also includes anATRAC compression encoder/decoder and a compressed data buffer memory.Furthermore, the audio processing unit 10 includes in its output sectiona digital audio data output part, a D/A converter, and an analog audiosignal output part made of a line output circuit and a headphone outputcircuit.

If the disc 90 is a current MD system disc and if audio tracks are to berecorded to the disc 90, digital audio data (or analog audio signals)are input to the audio processing unit 10. The input data are linear PCMdigital audio data or analog audio signals, which are converted tolinear PCM audio data through the A/D converter. The linear PCM audiodata are then subjected to ATRAC compression encoding before beingplaced into the buffer memory. The buffered data are then read from thememory in a suitably timed manner (i.e., in data increments equivalentto ADIP clusters) and transferred to the media drive unit 2. The mediadrive unit 2 subjects the compressed data thus transferred to an EFMprocess before writing the modulated data to the disc 90 as audiotracks.

If the disc 90 is a current MD system disc and if audio tracks are to bereproduced from the disc 90, the media drive unit 2 demodulates thereproduced data back to ATRAC-compressed data and transfers thedemodulated data to the audio processing unit 10 through the memorytransfer controller 3. The audio processing unit 10 subjects thereceived data to ATRAC compression decoding to acquire linear PCM audiodata which are output through the digital audio data output part.Alternatively, the received data are converted by the D/A converter toanalog audio signals, which are output through the line output orheadphone output part.

The disc drive unit 1 may be connected to the personal computer 100 in amanner other than through the USB arrangement. Illustratively, anexternal interface such as IEEE (Institute of Electrical and ElectronicsEngineers) 1394 may be utilized for the connection.

Read and write data are managed using the FAT system. How conversion iseffected between recording blocks and FAT sectors is discussed in detailin Applicants' Japanese Patent Application No. 2001-289380, filed in theJapanese Patent Office in 2001, the entire contents of which beingincorporated herein by reference.

Updating a FAT sector, as described above, involves first accessingrecording block (RB) containing the FAT sector in question and thenreading the recording block data from the disc. The retrieved data arewritten to the cluster buffer memory 4 and the FAT sector of thatrecording block is updated therein. With its FAT sector updated, therecording block is written back to the disc from the cluster buffermemory 4.

The recordable area is not initialized on the next-generation MD1 or MD2disc. This means that if a given recording block has yet to be used uponFAT sector update, an attempt to read the recording block data willresult in a data reproduction error because no RF signal is obtained.With no data retrieved from the disc, the FAT sector cannot be updated.

Reading a FAT sector also involves first accessing the recording blockcontaining the FAT sector in question and then reading the recordingblock data from the disc. The retrieved data are written to the clusterbuffer memory 4 so as to extract the target FAT sector data from therecording block. Since the recordable area is not initialized, if therecording block in question has yet to be used, the attempt to extractthe data will also fail or will result in erroneous data reproductionwith no RF signal obtained.

The failure discussed above is circumvented by determining whether theaccessed recording block has ever been used in the past. If therecording block is judged unused, the recording block data are not read.

More specifically, a signal recording bitmap (SRB) is created toindicate whether each of the recording blocks represented by a recordingblock number have ever been used, as shown in FIG. 20. In the signalrecording bitmap, a bit “0” is set for each recording block that hasnever had data written thereto; and a bit “1” is set for the recordingblock that has data written thereto at least once.

FIG. 21 is a flowchart of steps performed when a personal computerconnected to a disc drive unit compatible with the next-generation MD1and MD2 discs reads data in increments of FAT sectors from the discloaded in the disc drive unit.

In step S1 of FIG. 21, the computer issues a command to read data from aFAT sector, and the number of the recording block containing the FATsector in question is obtained. The sector number in this case is anabsolute sector number, with number 0 representing the beginning of theuser area on the disc. In step S2, a check is made to see whether theFAT sector has been replaced by an alternate sector.

If in step S2 the FAT sector is not judged to have been replaced by analternate sector, this means the target FAT sector is included in therecording block whose number was obtained in step S1. In that case, stepS3 is reached in which the bit (0 or 1) corresponding to the recordingblock number is acquired from the signal recording bitmap.

If in step S2 the FAT sector in question is judged to have been replacedby an alternate sector, an actual read/write operation is to be carriedout on the alternate sector. In that case, step S4 is reached in whichthe recording block number representing the actual alternate sector isobtained from a DDT alternate table. Step S4 is followed by step S3 inwhich the bit (0 or 1) corresponding to the number of the recordingblock containing the alternate sector is acquired from the signalrecording bitmap.

The signal recording map is structured as shown in FIG. 20. If no datahave yet to be written to a given recording block, the bit correspondingto that block is illustratively “0”; if data have been written to arecording block at least once, the corresponding bit for that block isillustratively “1.” Step S3 is followed by step S5 in which the signalrecording bitmap is referenced to see whether the recording block inquestion has had data written thereto in the past.

If in step S5 the bit is judged to be “1” corresponding to the recordingblock number in question in the signal recording bitmap (i.e., therecording block has had data written thereto in the past), then step S6is reached. In step S6, the recording block data are read from the discand written to the cluster buffer memory 4. In step S7, the datacorresponding to the target FAT sector are extracted from inside thecluster buffer memory 4 and output as read data.

If in step S5 the bit is judged to be “0” corresponding to the recordingblock number in question in the signal recording bitmap (i.e., therecording block has had no data written thereto so far), then step S8 isreached. In step S8, the entire cluster buffer memory 4 is filled withzeros. Step S8 is followed by step S7 in which the data corresponding tothe target FAT sector are extracted from inside the cluster buffermemory 4 and output as read data.

FIG. 22 is a flowchart of steps carried out when the personal computerconnected to the disc drive unit compatible with the next-generation MD1and MD2 discs writes data in increments of FAT sectors to the discloaded in the disc drive unit.

In step S11 of FIG. 22, the computer issues a command to write data to aFAT sector, and the number of the recording block containing the FATsector in question is obtained. The sector number in this case is alsoan absolute sector number, with number 0 representing the beginning ofthe user area on the disc. In step S12, a check is made to see whetherthe FAT sector has been replaced by an alternate sector.

If in step S12 the FAT sector in question is not judged to have beenreplaced by an alternate sector, that means the target FAT sector isincluded in the recording block whose number was obtained in step S11.In this case, step S13 is reached in which the bit (0 or 1)corresponding to the recording block number is acquired from the signalrecording bitmap.

If in step S12 the FAT sector is judged to have been replaced by analternate sector, an actual read/write operation is to be carried out onthe alternate sector. In that case, step S14 is reached in which therecording block number representing the actual alternate sector isobtained from the DDT alternate table. Step S14 is followed by step S13in which the bit (0 or 1) corresponding to the number of the recordingblock containing the alternate sector is acquired from the signalrecording bitmap.

The signal recording map is structured as shown in FIG. 20. If no datahave yet to be written to a given recording block, the bit correspondingto that block is illustratively “0”; if data have been written to arecording block at least once, the corresponding bit for that block isillustratively “1.” Step S13 is followed by step S15 in which the signalrecording bitmap is referenced to see whether the recording block inquestion has had data written thereto in the past.

If in step S15 the bit is judged to be “1” corresponding to therecording block number in question in the signal recording bitmap (i.e.,the recording block has had data written thereto in the past), then stepS16 is reached. In step S16, the recording block data are read from thedisc and written to the cluster buffer memory 4. In step S17, the datacorresponding to the target FAT sector in the recording block arereplaced with write data inside the cluster buffer memory 4.

If in step S15 the bit is judged to be “0” corresponding to therecording block number in question in the signal recording bitmap (i.e.,the recording block has had no data written thereto so far), then stepS18 is reached. In step S18, the entire cluster buffer memory 4 isfilled with zeros. Step S18 is followed by step S17 in which the datacorresponding to the target FAT sector in the recording block arereplaced with the write data inside the cluster buffer memory 4.

After the data corresponding to the target FAT sector in the recordingblock of interest are replaced with the write data in step S17, step S19is reached. In step S19, the recording block data are written to thedisc.

As described, when data are written to or read from a FAT sector, acheck is made to see if the recording block containing that FAT sectorhas ever been used. If the recording block is judged unused, data arenot read from the recording block, and the entire cluster buffer memory4 is filled with zeros. This allows the unused recording block to behandled as having an initial value of 0. As a result, no error occurswhen data are written or read in increments of FAT sectors even if therecording block containing the target FAT sector has never been used andan RF signal is not acquired.

In the preceding examples, data are written to or read from the targetFAT sector in a setup where the personal computer is connected to thedisc drive unit compatible with the next-generation MD1 and MD2 discs.In such cases, the FAT sector is designated by the personal computerusing an absolute sector number, with number 0 representing thebeginning of the user area. By contrast, if the disc drive unit alone isused to write or read data to or from the target FAT sector on the disc,the FAT sector is identified using a file directory entry and a FATchain, as shown in FIGS. 23 and 24.

FIG. 23 is a flowchart of steps in which the disc drive unit alone readsdata from a FAT sector of a next-generation MD1 or MD2 disc.

In step S21 of FIG. 23, the relative cluster number of the FAT clustercontaining the target FAT sector is obtained. In step S22, the absolutecluster number of the first FAT cluster is acquired from the filedirectory entry. In step S23, a FAT table chain is followed from thestarting absolute cluster number thus acquired, until the absolutecluster number of the target FAT cluster is obtained. In step S24, theabsolute sector number of the target FAT sector is acquired from theabsolute cluster number of the target FAT cluster. With the absolutesector number of the target FAT sector thus acquired, step S25 isreached in which data are read from the FAT sector. The sector datareading process is the same as that shown in FIG. 21.

FIG. 24 is a flowchart of steps in which the disc drive unit alonewrites data to a FAT sector of a next-generation MD1 or MD2 disc.

In step S31 of FIG. 24, the relative cluster number of the FAT clustercontaining the target FAT sector is obtained. In step S32, the absolutecluster number of the first FAT cluster is acquired from the filedirectory entry. In step S33, the FAT table chain is followed from thestarting absolute cluster number thus acquired, until the absolutecluster number of the target FAT cluster is obtained. In step S34, theabsolute sector number of the target FAT sector is obtained from theabsolute cluster number of the target FAT cluster. With the absolutesector number of the target FAT sector thus acquired, step S35 isreached in which data are written to the FAT sector. The sector datawriting process is the same as that shown in FIG. 22.

In the preceding examples, the signal recording bitmap shown in FIG. 20is used to determine whether the recording block containing the targetFAT sector has ever been used before. The FAT is illustratively managedin increments of 32-kilobyte FAT clusters. Using the FAT informationmakes it possible to check whether any given FAT sector has been used inthe past. Based on the FAT information, it is possible to create asignal recording bitmap showing illustratively whether each of the64-kilobyte recording blocks has already been used at least once.

FIG. 25 is a flowchart of steps for generating a signal recording bitmapusing FAT information. In step S41 of FIG. 15, with the disc loaded, thevalues representative of the recording blocks in the signal recordingbitmap are all reset to zero. In step S42, the FAT information is read.In step S43, the first FAT entry is accessed.

From the first FAT entry to the last, checks are made to see whethereach of the FAT clusters involved has ever been used so far. That bit inthe signal recording bitmap, which corresponds to any unused FATcluster, is left intact at “0”; those bits in the signal recordingbitmap, which correspond to used FAT clusters, are each set to “1.”

That is, with the first FAT entry accessed in step S43, step S44 isreached in which a check is made to see if the currently checked entryis the last FAT entry. If in step S44 the currently checked entry is notjudged to be the last FAT entry, step S45 is reached. In step S45, acheck is made to see whether the currently checked FAT entry is a usedFAT cluster.

If in step S45 the currently checked FAT entry is judged to be an unusedFAT cluster, step S46 is reached in which the next FAT entry is reached.From step S46, control is returned to step S44.

If in step S45 the currently checked FAT entry is judged to be a usedFAT cluster, step S47 is reached in which the number of the recordingblock containing the FAT cluster in question is obtained. In step S48,the bit corresponding to the recording block is set to “1” in the signalrecording bitmap. In step S49, the next FAT entry is reached. From stepS49, control is returned to step S44.

Repeatedly performing steps S44 through S49 generates a signal recordingbitmap in which the bits corresponding to unused FAT clusters are leftunchanged at “0” while the bits corresponding to used FAT clusters areeach set to “1.”

If in step S44 the currently checked FAT entry is judged to be the lastFAT entry, then step S50 is reached in which the signal recording bitmapis deemed complete.

As described, using the FAT information makes it possible to create thesignal recording bitmap. Depending on the operating system, however, theFAT clusters judged used based on the FAT information may not signifythose with data actually written thereto in the past. Under such anoperating system, some FAT clusters may be judged already used but infact they are unused.

The above conflict is avoided by writing the signal recording bitmap tothe disc. As illustrated in FIGS. 2 and 4, the next-generation MD1 andMD2 discs have a reserve track each between the DDT track and the FATtrack. The reserve track may be used to retain a signal recording bitmapthat accommodates signal recording bitmap information shown in FIG. 20.

If the location of the track to which to record the signal recordingbitmap is determined in advance by the system, the bitmap can beaccessed directly based on its predetermined location. The DDT track andFAT track may also be accessed directly if their locations aredetermined beforehand by the system. Obviously, the locations of thesespecial tracks may alternatively be recorded in the management area(U-TOC on the next-generation MD1 disc; control area containingADIP-based control information on the next-generation MD2 disc). Thedata from the DDT track and FAT track are read when the disc is loaded,and are placed into a buffer memory. The data thus retrieved are used asthe basis for generating alternate sector information and FATinformation. These items of information in the buffer memory are updatedwhile the disc is being used. When the disc is ejected, the updatedalternate sector information and FAT information are written back to theDDT track and FAT track. Writing or reading the signal recording bitmapto or from its recording track is done basically the same way as writingor reading the data to or from the DDT track and FAT track.

When the disc is loaded, the signal recording bitmap information is readfrom its recording track and placed into the memory. Every time data arewritten anew to a recording block, the corresponding signal recordingbitmap entry is updated in the memory. When the disc is ejected, theupdated signal recording bitmap is read from the memory and written tothe signal recording bitmap track on the disc.

FIG. 26 is a flowchart of steps for reading information from the signalrecording bitmap track. In step S61 of FIG. 26, with the disc loaded,information is read from the signal recording bitmap track of the disc.In step S62, the information read from the signal recording bitmap trackis written to the memory and turned into a signal recording bitmap.

FIG. 27 is a flowchart of steps for writing the signal recording bitmapback to the signal recording bitmap track on the disc. In the memory,the signal recording bitmap is updated every time data are written anewto any recording block.

In step S71 of FIG. 27, when the disc is ejected, the updated signalrecording bitmap is read from the memory. In step S72, the updatedsignal recording bitmap thus retrieved is written to the signalrecording bitmap track on the disc.

In its initial state, the information held in the signal recordingbitmap track is all zeros. Upon each use of the disc, those bits in thesignal recording bitmap, which correspond to the recording blockssubjected to data write operations, are each updated to “1.” Thisinformation in the signal recording bitmap is written back to the signalrecording bitmap track on the disc. Next time the disc is loaded foruse, the information is read from the signal recording bitmap track andturned into a signal recording bitmap in the memory. These steps make itpossible to generate the signal recording bitmap without recourse to theFAT information.

Described below with reference to FIG. 17 is a typical structure of themedia drive unit 2 capable of writing and reading data to and from boththe data tracks and the audio tracks of the disc.

As illustrated in FIG. 17, the media drive unit 2 has a turntable thatmay accommodate three kinds of discs: a current MD system disc, anext-generation MD1 disc, and a next-generation MD2 disc. The disc 90placed on the turntable is rotated by a spindle motor 29 on a CLV basis.For a write or read operation on the disc 90, an optical head 19 emits alaser beam onto the disc surface.

For the write operation, the optical head 19 outputs a laser beam at alevel high enough to heat the recording track up to the Curietemperature; for the read operation, the optical head 19 outputs a laserbeam at a relative low level sufficient to detect data from thereflected light based on the magnetic Kerr effect. In order to implementthese capabilities, the optical head 19 incorporates a laser diode aslaser outputting means, an optical system made up of a polarization beamsplitter and an objective lens, and a detector arrangement for detectingthe reflected light, not shown. The objective lens in the optical head19 is held illustratively by a dual axis mechanism in both radially andperpendicularly displaceable relation with the disc surface.

A magnetic head 18 is positioned in symmetrically opposite relation tothe optical head 19 across the disc 90. The magnetic head 18 applies tothe disc 90 a magnetic field so modulated as to represent write data.Although not shown, there are a sled motor and a sled mechanism formoving the optical head 19 in its entirety and the magnetic head 18 inthe radial direction of the disc.

The optical head 19 and magnetic head 18 execute a pulse-driven magneticfield modulation process to form infinitesimal markings on thenext-generation MD2 disc. On the current MD system disc ornext-generation MD1 disc, the optical head 19 and magnetic head 18 carryout a DC emission magnetic field modulation process.

The media drive unit 2 also includes a recording processing section, areproduction processing section, and a servo section in addition to therecording/reproducing head section made up of the optical head 19 andmagnetic head 18, and the disc rotation drive section formed by thespindle motor 29.

One of three kinds of discs 90 may be loaded: the current MD systemdisc, the next-generation MD1 disc, or the next-generation MD2 disc.Linear velocity varies with the disc type. The spindle motor 29 iscapable of rotating each loaded disc 90 at a speed compatible with thedisc type in question. That is, the disc 90 placed on the turntable isrotated at a linear velocity corresponding to one of the three usabledisc types above.

The recording processing section includes two portions: one adoptingACIRC for error correction and EFM for data modulation in order to writeerror-corrected modulated data to audio tracks on the current MD systemdisc, and the other portion utilizing BIS and LDC in combination forerror correction and the 1-7 pp modulation for data modulation so as towrite error-corrected modulated data to the next-generation MD1 or MD2system disc.

The reproduction processing section includes two portions: one adoptingEFM for data demodulation and ACIRC for error correction in reproducingdata from the current MD system disc, and the other portion utilizingthe 1-7 demodulation based on data detection using the partial responsescheme and Viterbi decoding method for data reproduction from thenext-generation MD1 or MD2 system disc.

The reproduction processing section further includes a portion fordecoding ADIP signal-based addresses used by the current MD system or bythe next-generation MD1 system , and a portion for decoding the ADIPsignal adopted by the next-generation MD2 system.

Laser emission from the optical head 19 onto the disc 90 produces areflected light beam representative of information detected from thedisc. The detected information, i.e., a photoelectric current obtainedby a photo detector detecting the reflected laser beam, is sent to an RFamplifier 21.

The RF amplifier 21 subjects the detected information thus received tocurrent-to-voltage conversion, amplification, and matrix computation inorder to extract reproduced information including a reproduced RFsignal, a tracking error signal TE, a focus error signal FE, and grooveinformation (ADIP information recorded as track wobbles on the disc 90).

When data are reproduced from the current MD system disc, the reproducedRF signal obtained by the RF amplifier 21 is processed by an EFMdemodulation unit 24 and an ACIRC decoder 25. More specifically, the EFMdemodulation unit 24 binarizes the reproduced RF signal into an EFMsignal train before submitting it to EFM demodulation. The demodulatedsignal is subjected to error correction and de-interleave processing bythe ACIRC decoder 25. At this point, ATRAC-compressed data are obtained.

Upon data reproduction from the current MD system disc, a selector 26 isset to contact B. In that setting, the selector 26 allows thedemodulated ATRAC-compressed data to be output as the reproduced datafrom the disc 90.

When data are reproduced from the next-generation MD1 or MD2 disc, thereproduced RF signal obtained by the RF amplifier 21 is fed to anRLL(1-7)PP demodulation unit 22 and an RS-LDC decoder 23. Morespecifically, given the reproduced RF signal, the RLL(1-7)PPdemodulation unit 22 performs data detection through PR(1, 2, 1)ML orPR(1, −1)ML and Viterbi decoding to acquire an RLL(1-7) code train asreproduced data. The demodulation unit 22 subjects the RLL(1-7) codetrain to RLL(1-7) demodulation. The demodulated data are fed to theRS-LDC decoder 23 for error correction and de-interleave processing.

Upon data reproduction from the next-generation MD1 or MD2 disc, theselector 26 is set to contact A. The selector 26 in that setting allowsthe demodulated data to be output as the reproduced data from the disc90.

The tracking error signal TE and focus error signal FE from the RFamplifier 21 are sent to a servo circuit 27. The groove information fromthe RF amplifier 21 is supplied to an ADIP demodulation unit 30.

The ADIP demodulation unit 30 submits the received groove information toa band-pass filter to extract the wobble components, before effecting FMdemodulation and biphase demodulation to demodulate the ADIP signal. Thedemodulated ADIP signal is fed to address decoders 32 and 33.

On the current MD system disc or next-generation MD1 disc, the ADIPsector number is eight bits long, as shown in FIG. 9. On thenext-generation MD2 disc, by contrast, the ADIP sector number is fourbits long as illustrated in FIG. 11. The address decoder 32 decodes theADIP address from the current MD system disc or next-generation MD1disc, while the address decoder 33 decodes the ADIP address from thenext-generation MD2 disc.

The ADIP address decoded by the address decoder 32 or 33 is sent to adrive controller 31. Given the ADIP address, the drive controller 31carries out necessary control processing. The groove information fromthe RF amplifier 21 is also fed to the servo circuit 27 for spindleservo control.

The servo circuit 27 integrates phase differences between the receivedgroove information and a reproduced clock signal (PLL clock signal ineffect upon decoding) to obtain an error signal. Based on the errorsignal thus acquired, the servo circuit 27 generates a spindle errorsignal for CLV or CAV servo control.

The servo circuit 27 generates various servo control signals (e.g.,tracking control signal, focus control signal, sled control signal, andspindle control signal) based on the spindle error signal, on thetracking error signal and focus error signal from the RF amplifier 21,or on a track jump command and an access command from the drivecontroller 31. The servo control signals thus generated are output to amotor driver 28. More specifically, the servo circuit 27 subjects theservo error signals and commands to such processes as phasecompensation, gain processing, and target value setting in order togenerate the diverse servo control signals.

The motor driver 28 generates servo drive signals based on the servocontrol signals fed from the servo circuit 27. The servo drive signalsgenerated by the motor driver 28 are made up of dual axis drive signalsfor driving the dual axis mechanism (two signals for driving in focusingand tracking directions), a sled motor drive signal for driving the sledmechanism, and a spindle motor drive signal for driving the spindlemotor 29. These servo drive signals provide focus and tracking controlon the disc 90 and CLV or CAV control over the spindle motor 29.

When audio data are to be recorded to the current MD system disc, aselector 16 is set to contact B. The selector setting allows the ACIRCencoder 14 and EFM modulation unit 15 to function. In this setup, thecompressed data coming from the audio processing unit 10 are subjectedto interleave processing and error correction coding by the ACIRCencoder 14. The output of the ACIRC encoder 14 is submitted to EFMprocessing by the EFM modulation unit 15.

The EFM-modulated data are fed to a magnetic head driver 17 through theselector 16. The magnetic head 18 applies to the disc 90 a magneticfield representative of the EFM-modulated data, whereby the data arewritten to audio tracks on the disc 90.

When audio data are to be recorded to the next-generation MD1 or MD2disc, the selector 16 is set to contact A. That setting allows an RS-LDCencoder 12 and an RLL(1-7)PP modulation unit 13 to function. In thissetup, high-density data coming from the memory transfer controller 3are subjected to interleave processing and RS-LDC-based error correctioncoding by the RS-LDC encoder 12. The output of the RS-LDC encoder 12 issubmitted to RLL(1-7) modulation by the RLL(1-7)PP modulation unit 13.

The write data in the form of an RLL(1-7) code train are fed to themagnetic head driver 17 through the selector 16. The magnetic head 18applies to the disc 90 a magnetic field representative of the modulateddata, whereby the data are written to audio tracks on the disc 90.

The purpose of a laser driver/APC 20 is twofold: to cause the laserdiode to emit a laser beam during the read and write operations asdescribed above, and to effect so-called APC (Automatic Laser PowerControl).

Although not shown, a detector for monitoring the laser power level isincorporated in the optical head 19. A monitor signal from the detectoris fed back to the laser driver/APC 20. The laser driver/APC 20 comparesthe current laser power level acquired as the monitor signal with anestablished laser power level to find an error difference. By gettingthat error difference reflected in the laser drive signal, the laserdriver 20 keeps the laser power from the laser diode stabilized at theestablished level.

Two laser power levels, i.e., a read laser power level and a write laserpower level, are set by the drive controller 31 to registers inside thelaser driver/APC 20.

Under control of the system controller 9, the drive controller 31 seesto it that the controlled operations described above (access, servooperations, data write operation, and data read operation) are properlycarried out.

In FIG. 17, portions A and B enclosed by dashed lines may each beimplemented as a single-chip circuit part.

5. Initialization of Next-Generation MD1 and MD2 discs

On both the next-generation MD1 disc and the next-generation MD2 disc, aunique ID (UID) is recorded in addition to the FAT for securitymanagement purposes as mentioned earlier. On each next-generation MD1 orMD2 disc, in principle, the UID is recorded to a predetermined locationsuch as in the lead-in area before the disc is shipped from the factory.Alternatively, the UID may be written elsewhere on the disc. As long asthe UID is written to a fixed location after disc initialization, theUID may be recorded to that location beforehand.

The next-generation MD1 system utilizes the same disc as that of thecurrent MD system. That means a huge number of current MD system discsalready marketed with no UID recorded on any of them are to be used bythe next-generation MD1 system .

New standards have thus been established to allocate a specificallyprotected area on each of these numerous current MD system discs thatmay be utilized by the next-generation MD1 system . Upon initializationof any of these discs, the disc drive unit 1 writes a random numbersignal to the protected area for use as the UID of the disc in question.Under new standards, users are prohibited from accessing the UID-filledarea. The UID is not limited to random number signals; it may be givenas the combination of a manufacturer code, an equipment code, anequipment serial number, and a random number. It is also possible tocombine at least one of the manufacturer code, equipment code, andequipment serial number, with a random number for use as the UID.

FIG. 18 is a flowchart of steps for initializing a next-generation MD1disc. In the first step S100 of FIG. 18, a predetermined location on thedisc is accessed to determine whether a UID is recorded there. If a UIDis judged as being recorded, the UID is read and placed temporarilyinto, say, the auxiliary memory 5.

The location to be accessed in step S100 is an area outside the FAT areain the next-generation MD1 system format, such as the lead-in area. Ifthe disc 90 in question was initialized in the past and is alreadyfurnished with a DDT area, that area may be accessed instead. Step S100may be skipped where appropriate.

In step S101, data are recorded to the U-TOC area in an EFM modulationprocess. Written at this point to the U-TOC is information for securingtwo kinds of areas: an alert track, and an area of tracks following theDDT area, i.e., an area in which data are to be recorded in 1-7 ppmodulation format. In step S102, data are written to the alert track inEFM format. In step S103, data are written to the DDT area in 1-7 ppmodulation format.

In step S104, a UID is recorded outside the FAT area such as in the DDTarea. If the UID was read from its predetermined location and placedinto the auxiliary memory 5 in step S100 above, that UID is recordedhere. If in step S100 the UID was not judged as being written in apredetermined location on the disc or if step S100 is skipped outright,a UID is generated based on a random number signal and the generated UIDis recorded. The UID is generated illustratively by the systemcontroller 9. The generated UID is fed to the media drive unit 2 via thememory transfer controller 3 before being written to the disc 90.

In step S105, FAT and other data are written to the area for datastorage in 1-7 pp modulation format. In other words, the UID is recordedoutside the FAT area. For the next-generation MD1 system , as describedabove, initialization of the recordable area managed under the FATscheme is not mandatory.

FIG. 19 is a flowchart of steps for initializing a next-generation MD2disc. In the first Step S110 0f FIG. 19, a predetermined location wherea UID is supposed to be recorded beforehand such as the lead-in area, orthe DDT area if the disc was initialized in the past, is accessed todetermine whether a UID is recorded there. If the UID is judgedrecorded, that UID is read and placed temporarily in, say, the auxiliarymemory 5. Because the UID recording location is fixedly determined inthe format, it can be accessed directly without reference to any othermanagement information on the disc. This feature may also be applied tothe processing discussed above with reference to FIG. 18.

In step S111, data are recorded to the DDT area in 1-7 pp modulationformat. In step S112, the UID is recorded outside the FAT area such asin the DDT area. The UID recorded at this point is the UID that wasretrieved from the predetermined location on the disc and placed intothe auxiliary memory 5 in step S110. If in step S110 the UID was notjudged recorded in the predetermined location on the disc, then a UID isgenerated on the basis of a random number signal, and the generated UIDis written. The UID is generated illustratively by the system controller9. The generated UID is fed to the media drive unit 2 via the memorytransfer controller 3 before being written to the disc 90.

In step S113, FAT and other data are recorded. The UID is recordedoutside the FAT area. For the next-generation MD2 system, as describedabove, initialization of the recordable area managed under the FATscheme is not effected.

6. First Example of the Audio Data Management System

As discussed above, the next-generation MD1 and MD2 systems embodyingthis invention have their data managed by the FAT system. Audio data tobe recorded are compressed by a predetermined data compression methodand encrypted for copyright protection. The audio data compressionmethod is illustratively ATRAC3 or ATRAC5. It is also possible to adoptMP3 (MPEG1 Audio Layer 3), AAC (MPEG2 Advanced Audio Coding), or othersuitable compression method. Not only audio data but also still imagedata and moving image data may be handled. Since the FAT system is inuse, general-purpose data may also be recorded and reproduced by thenext-generation MD1 and MD2 systems. Furthermore, computer-readable andexecutable instructions may be encoded on the disc so the MD1 or MD2 mayalso contain executable files.

Described below is a system for managing audio data as they are recordedand reproduced to and from the next-generation MD1 and MD2 discs.

Because the next-generation MD1 and MD2 systems are designed toreproduce high-quality audio data for extended periods of time, thereare a large number of audio data items to be managed on a single disc.Since the FAT system is adopted for data management purposes, bettercompatibility with computers is ensured. This feature, however, asrecognized by the present inventors, has its advantages anddisadvantages. Whereas the ease of operation is enhanced on the part ofusers, audio data could be copied illegally to the detriment ofcopyright holders. These characteristics were especially taken intoconsideration in the development of the inventive audio data managementsystem.

FIG. 28 is an explanatory view of a first example of the audio datamanagement system. As shown in FIG. 28, the audio data management systemin its first-example setup generates a track index file and an audiodata file on the disc. These are the files managed by the FAT system.

The audio data file is a file that accommodates a plurality of audiodata items as illustrated in FIG. 29. When viewed from the FAT system,the audio data file appears to be a very large file. The inside of thisfile is divided into parts, so that audio data are handled as a set ofsuch parts.

The track index file is a file that describes various types ofinformation for managing the audio data contained in the audio datafile. As shown in FIG. 30, the track index file is made up of a playorder table, a programmed play order table, a group information table, atrack information table, a part information table, and a name table.

The play order table indicates the order of audio data reproductiondefined by default. As shown in FIG. 31, the play order table containsinformation items TINF1, TINF2, etc., representing links to trackdescriptors (FIG. 34A) corresponding to track numbers (i.e., music titlenumbers) in the track information table. Track numbers areillustratively serial numbers starting from “1.”

The programmed play order table contains the order of audio datareproduction defined by the individual user. As shown in FIG. 32, theprogrammed play order table describes programmed track information itemsPINF1, PINF2, etc., representing links to the track descriptorscorresponding to the track numbers.

The group information table, as depicted in FIGS. 33A and 33B, describesinformation about groups. A group is defined as a set of one or moretracks having serial track numbers, or a set of one or more tracks withprogrammed serial track numbers. Specifically, the group informationtable is made of group descriptors representing track groups as shown inFIG. 33A. Each group descriptor describes a start track number, an endtrack number, a group name, and a flag regarding the group in questionas indicated in FIG. 33B.

The track information table describes information about tracks, i.e.,music titles as shown in FIGS. 34A and 34B. Specifically, the trackinformation table is made up of track descriptors representing tracks(music titles) as indicated in FIG. 34A. Each track descriptor, asdepicted in FIG. 34B, contains a coding system, copyright managementinformation, content decryption key information, pointer informationpointing to the part number serving as the entry to the music title ofthe track in question, an artist name, a title name, original titleorder information, and recording time information about the track inquestion. The artist name and title name do not contain actual names butdescribe pointer information pointing to relevant entries in the nametable. The coding system represents a codec operating scheme serving asdecryption information.

The part information table describes pointers allowing part numbers topoint to actual music title locations as shown in FIGS. 35A and 35B.Specifically, the part information table is made up of part descriptorscorresponding to parts as depicted in FIG. 35A. A part is representativeof one track in its entirety or one of multiple parts constituting asingle track. FIG. 35B indicates entries of a part descriptor in thepart information table. As shown in FIG. 35B, each part descriptor iscomposed of a start address and an end address of the part in questionin the audio data file, and a link to the next part.

The addresses used as part number pointer information, name tablepointer information, and audio file location pointer information mayeach be given in the form of a file byte offset, a part descriptornumber, a FAT cluster number, or a physical address of a disc utilizedas a storage medium. The file byte offset is a specific implementationof an offset scheme that may be implemented according to the presentinvention, where the part pointer information is an offset value inpredetermined units (e.g., bytes, bits, and n-bit blocks) from abeginning of the audio file.

The name table is a table of text making up actual names. As shown inFIG. 36A, the name table is made of a plurality of name slots. Each nameslot is linked with and called by a pointer pointing to the name inquestion. A pointer for calling up a name may be an artist name or atitle name in the track information table, or a group name in the groupinformation table. One name slot may be called from a plurality ofpointers. As depicted in FIG. 36B, each name slot is composed of namedata constituting text information, a name type serving as an attributeof the text information, and a link to another name slot. A name toolong to be accommodated in a single name slot may be divided into aplurality of name slots. The divided name slots are traced one afteranother using links describing the whole name.

The first example of the audio data management system according to theinvention works as follow: as illustrated in FIG. 37, the track numberof a target track to be reproduced is first designated in the play ordertable (FIG. 31). With the track number designated, access is gainedthrough a link to the track descriptor (FIGS. 34A and 34B) in the trackinformation table, and the linked track descriptor is retrieved from thetable. Read from the track descriptor are: a coding system, copyrightmanagement information, content decryption key information, pointerinformation pointing to the part number serving as the entry to themusic title of the track in question, an artist name pointer, a titlename pointer, original title order information, and recording timeinformation about the track in question.

Based on the part number information read from the track informationtable, access is gained through a link to the applicable part descriptorin the part information table (FIGS. 35A and 35B). From the partinformation table, the audio data file is accessed at the partcorresponding to the start address of the track (title) in question.When access is gained to the data at the part whose location in theaudio data file is designated by the part information table,reproduction of audio data is started from that location. At this time,the reproduced data are decrypted in accordance with the coding systemread from the applicable track descriptor in the track informationtable. If the audio data are encrypted, the key information read fromthe track descriptor is used to decrypt the data.

If there is any part following the part in question, a link to thedestination part is described in the part descriptor. The relevant partdescriptors are read one after another in accordance with the links, sothat the audio data in the audio data file are reproduced from the partswhose locations are designated by the accessed part descriptors. Thesesteps allow the audio data to be reproduced from the desired track(music title).

A name slot (FIG. 36A) in the name table is called from the location (orname pointer information) designated by an artist name pointer or atitle name pointer read from the track information table. Name data areread from the name slot thus called. The name pointer information may bea name slot number, a cluster number in a file allocation table system,or a physical address of a storage medium, for example.

Each name slot in the name table may be referenced from a plurality ofpointers as mentioned above. For example, where multiple titles of thesame artist are recorded, the same name slot in the name table isreferenced from a plurality of pointers in the track information tableas shown in FIG. 38. In the example of FIG. 38, track descriptors “1,”“2,” and “4” represent the music titles all belonging to the same artist“DEF BAND,” so that the same name slot is referenced from each of thesetrack descriptors. Also in FIG. 38, track descriptors “3,” “5,” and “6”represent the music titles all belonging to the same artist “GHQ GIRLS,”so that the same name slot is also referenced from each of these trackdescriptors. When each name slot in the name table is allowed to bereferenced from a plurality of pointers, the size of the name table canbe reduced appreciably.

Furthermore, information about a given artist name may be displayed byuse of links to the name table. If it is desired to display a list ofmusic titles belonging to, say, the artist named “DEF BAND,” the trackdescriptors referencing the same name slot “DEF BAND” are traced andtheir information is displayed. In this example, the track descriptors“1,” “2,” and “4” referencing the address in the name slot “DEF BAND”are traced and the descriptor information is acquired. The informationthus obtained permits a display of the music titles which belong to theartist named “DEF BAND” and which are held on this disc. There are nolinks going from the name table back to the track information table,because each name slot in the name table is allowed to be referencedfrom a plurality of pointers.

When audio data are to be recorded anew, an unused area made up of atleast a predetermined number of consecutive recording blocks (e.g., fourrecording blocks) is allocated according to the FAT table. Recordingblocks are allocated consecutively so as to minimize wastage inaccessing the recorded audio data.

When the audio data recordable area is allocated, a new track descriptoris assigned to the track information table, and a content key forencrypting the audio data in question is generated. The input audio dataare encrypted using the key before getting recorded to the unused areaallocated. The area in which the audio data have been recorded ischained to the tail end of the audio data file in the FAT file system.

With the new audio data chained to the audio data file, informationabout the chained location is generated, and the newly generated audiodata location information is written to a newly assigned partdescriptor. Key information and a part number are written to the newtrack descriptor. If necessary, an artist name and a title name arewritten to relevant name slots. In the track descriptor, pointers aredescribed with links to the artist name and title name. The number ofthe track descriptor in question is written to the play order table, andthe applicable copyright management information is updated.

When audio data are to be reproduced from a particular track,information about the designated track number is retrieved from the playorder table. The track descriptor corresponding to the track from whichto reproduce the audio data is then acquired.

Key information is obtained from the applicable track descriptor in thetrack information table, and the part descriptor indicating the areacontaining entry data is acquired. From the part descriptor, access isgained to the location, in the audio data file, of the first partcontaining the desired audio data, and data are retrieved from theaccessed location. The reproduced data from the location are decryptedusing the acquired key information for audio data reproduction. If thepart descriptor has a link to another part, the linked part is accessedand the above steps are repeated.

Suppose that it is desired to change a track number “n” of a given trackin the play order table into a track number “n+m.” In that case, a trackdescriptor Dn describing information about the track in question isfirst obtained from a track information item TINFn in the play ordertable. All values representing track information items TINFn+1 throughTINFn+m (i.e., track descriptor numbers) are advanced by one place. Thenumber of the track descriptor Dn is then written to the trackinformation item TINFn+m.

Suppose now that a track with a track number “n” is desired to beerased. In this case, the track descriptor Dn describing the informationabout the track is acquired from the track information item TINFn in theplay order table. All valid track descriptor numbers following the trackinformation entry TINFn+1 in the play order table are advanced by oneplace. Moreover, because the track “n” is to be erased, all trackinformation entries that follow track “n” are advanced in the play orderby one place. Based on the track descriptor Dn thus obtained for thetrack to be deleted, the coding system and the decryption keycorresponding to the track in question are acquired from the trackinformation table. Also acquired is the number of a part descriptor Pnindicating the area containing the start audio data. An audio block withits range designated by the part descriptor Pn is detached from theaudio data file in the FAT file system. Then the track descriptor Dn ofthe track in question is erased from the track information table and thepart descriptor is erased from the part information table so as to freethe part description on the file system.

Suppose that in FIG. 39A, parts A, B, and C have been chained and thatpart B is desired to be erased. It is assumed here that the parts A andB share the same audio block (and the same FAT cluster) and that the FATchain is continuous. It is also assumed that while the part C is locatedimmediately after the part B in the audio data file, the parts C and Bare in fact found positioned apart when the FAT table is checked.

In that case, as shown in FIG. 39B, erasing the part B allows two FATclusters not sharing any cluster with that part to be detached from theFAT chain (i.e., reverted to free areas). In other words, the audio datafile is shortened by four audio blocks. As a result, a number “4” issubtracted from each of the numbers of the audio blocks recorded in thepart C and subsequent parts.

Part of a track may be erased instead of the track as a whole. If atrack is partially erased, information about the remaining track may bedecrypted using the coding system and the decryption key whichcorrespond to the track in question and which are acquired from therelevant part descriptor Pn in the track information table.

If it is desired to combine a track “n” with a track “n+1” in the playorder table, a track descriptor number Dn is acquired from a trackinformation item TINFn in the play order table, the track descriptordescribing information about the track “n”; and a track descriptornumber Dm is obtained from a track information item TINFn+1 in the playorder table, the track descriptor describing information about the track“n+1.” All valid TINF values (track descriptor numbers) following theitem TINFn+1 in the play order table are advanced by one place. A searchis made through the programmed play order table in order to erase alltracks referencing the track descriptor Dm. A new encryption key isgenerated, and a part descriptor list is obtained from the trackdescriptor Dn. To the tail end of that part descriptor list, anotherpart descriptor list extracted from the track descriptor Dm is attached.

Where two tracks are to be combined, their track descriptors need to becompared so as to ascertain that the copyrights involved are notcompromised. Part descriptors need to be obtained from these trackdescriptors to make sure, with reference to the FAT table, thatfragmentation-related requirements are met upon combination of the twotracks. It may also be necessary to update pointers to the name table.

Where the track “n” is desired to be divided into a track “n” and atrack “n+1,” the track descriptor number Dn describing information aboutthe track “n” is first acquired from the track information item TINFn inthe play order table. From the track information item TINFn+1 in theplay order table, the track descriptor number Dm describing informationabout the track “n+1” is obtained. All valid TINF values (trackdescriptor numbers) following the track information item TINFn+1 in theplay order table are advanced by one place. A new key is generated forthe track descriptor Dn. The part descriptor list is extracted from thetrack descriptor Dn. A new part descriptor is allocated, and the partdescriptor content in effect before the track division is copied to thenewly allocated part descriptor. The part descriptor containing adividing point is shortened up to that point, and any part descriptorlinks subsequent to the dividing point are discarded. The newlyallocated part descriptor is set immediately after the dividing point.

7. Second Example of the Audio Data Management System

A second example of the audio data management system according to theinvention will now be described. FIG. 40 is an explanatory view of asecond-example setup of the inventive audio data management system. Asshown in FIG. 40, the audio data management system of this exampleinvolves generating a track index file and a plurality of audio datafiles on the disc. These files are managed by the FAT system.

Each audio data file, as shown in FIG. 41, accommodates audio dataconstituting a single music title (piece of music) in principle. Theaudio data file has a header that includes a title, decryption keyinformation, copyright management information, and index information.Indexes are used to divide one piece of music on a single track into aplurality of tracks. The header records the locations of index-dividedtracks in conjunction with index numbers. Illustratively, up to 255indexes may be set to a track.

The track index file is a file that describes various items ofinformation for managing the audio data retained in audio data files. Asshown in FIG. 42, the track index file is made up of a play order table,a programmed play order table, a group information table, a trackinformation table, and a name table.

The play order table indicates the order of audio data reproductiondefined by default. As shown in FIG. 43, the play order table containsinformation items TINF1, TINF2, etc., representing links to trackdescriptors (FIG. 46A) corresponding to track numbers (i.e., music titlenumbers) in the track information table. Track numbers areillustratively serial numbers starting from “1.”

The programmed play order table contains the order of audio datareproduction defined by the individual user. As shown in FIG. 44, theprogrammed play order table describes programmed track information itemsPINF1, PINF2, etc., representing links to the track descriptorscorresponding to the track numbers.

The group information table, as depicted in FIGS. 45A and 45B, describesinformation about groups. A group is defined as a set of one or moretracks having serial track numbers, or a set of one or more tracks withprogrammed serial track numbers. Specifically, the group informationtable is made of group descriptors representing track groups as shown inFIG. 45A. Each group descriptor describes a start track number, an endtrack number, a group name, and a flag regarding the group in questionas indicated in FIG. 45B.

The track information table describes information about tracks, i.e.,music titles as shown in FIGS. 46A and 46B. Specifically, the trackinformation table is made up of track descriptors representing tracks(music titles) as indicated in FIG. 46A. Each track descriptor, asdepicted in FIG. 46B, includes a file pointer pointing to the audio datafile of the track in question, an index number of the track, an artistname, a title name, original title order information, and recording timeinformation about the track. The artist name and title name do notcontain actual names but describe pointer information pointing torelevant entries in the name table.

The name table is a table of texts making up actual names. As shown inFIG. 47A, the name table is made of a plurality of name slots. Each nameslot is linked with and called by a pointer pointing to the name inquestion. A pointer for calling up a name may be an artist name or atitle name in the track information table, or a group name in the groupinformation table. One name slot may be called from a plurality ofpointers. As depicted in FIG. 47B, each name slot is composed of namedata, a name type, and a link to another name slot. A name too long tobe accommodated in a single name slot may be divided into a plurality ofname slots. The divided name slots are traced one after another usinglinks describing the whole name.

The second example of the audio data management system according to theinvention works as follow: as illustrated in FIG. 48, the track numberof a target track to be reproduced is first designated in the play ordertable (FIG. 43). With the track number designated, access is gainedthrough a link to the track descriptor (FIGS. 46A and 46B) in the trackinformation table, and the linked track descriptor is retrieved from thetable. Read from the track descriptor are: a file pointer pointing tothe audio data file in question, an index number of the track inquestion, an artist name pointer, a title name pointer, original titleorder information, and recording time information about the track.

Based on the audio data file pointer, the audio data file in question isaccessed and information is read from the header of the file. If theaudio data are encrypted, the key information read from the header isused to decrypt the data for audio data reproduction. If an index numberis designated, the location of the designated index number is detectedfrom the header information, and audio data reproduction is started fromthe location of that index number.

A name slot is called from the location designated by the artist namepointer or the title name pointer retrieved from the track informationtable. Name data are read from the name slot thus called.

When audio data are to be recorded anew, an unused area made up of atleast a predetermined number of consecutive recording blocks (e.g., fourrecording blocks) is allocated according to the FAT table.

When the audio data recordable area is allocated, a new track descriptoris assigned to the track information table, and a content key forencrypting the audio data in question is generated. The input audio dataare encrypted using the key, and an audio data file is generated withthe encrypted audio data.

A file pointer of the newly generated audio data file and keyinformation are written to the newly assigned track descriptor. Ifnecessary, an artist name and a title name are written to relevant nameslots. In the track descriptor, pointers are described with links to theartist name and title name. The number of the track descriptor inquestion is written to the play order table, and the applicablecopyright management information is updated.

When audio data are to be reproduced from a particular track,information about the designated track number is retrieved from the playorder table. The track descriptor corresponding to the track from whichto reproduce the audio data is then acquired.

Based on the track descriptor in the track information table, the filepointer pointing to the audio data file containing the desired audiodata and the index number of the track in question are obtained. Theaudio data file is then accessed and key information is acquired fromthe header of the file. The reproduced data from the audio data file aredecrypted using the acquired key information for audio datareproduction. Where the index number is designated, audio datareproduction is started from the location of the designated indexnumber.

Where a track “n” is desired to be divided into a track “n” and a track“n+1,” a track descriptor number Dn describing information about thetrack “n” is first acquired from a track information item TINFn in theplay order table. From a track information item TINFn+1, a trackdescriptor number Dm describing information about the track “n+1” isobtained. All valid TINF values (track descriptor numbers) following thetrack information item TINFn+1 in the play order table are advanced byone place.

As shown in FIG. 49, using an index arrangement allows data in one fileto be divided into a plurality of indexed areas. The index numbers beingused and the locations of the indexed areas are written to the header ofthe audio track file in question. An audio data file pointer and anindex number are written to one track descriptor Dn, and another audiodata file pointer and another index number are written to another trackdescriptor Dm. In this case, one piece of music M1 on a single track inthe audio data file is apparently divided into two pieces of music M11and M12 over two tracks.

If it is desired to combine a track “n” with a track “n+1” in the playorder table, a track descriptor number Dn describing information aboutthe track “n” is acquired from a track information item TINFn in theplay order table, and a track descriptor number Dm describinginformation about the track “n+1” is obtained from a track informationitem TINFn+1 in the play order table. All valid TINF values (trackdescriptor numbers) following the item TINFn+1 in the play order tableare advanced by one place.

If the track “n” and track “n+1” are found in the same audio data fileand separated from each other by an index, then erasing the indexinformation from the header of the file allows the tracks to be combinedas illustrated in FIG. 50. Two pieces of music M21 and M22 on the twotracks are thus combined into a single piece of music M23 on one track.

Suppose that the track “n” is the index-divided latter half of an audiodata file and that the track “n+1” is found at the beginning of anotheraudio data file. In that case, as shown in FIG. 51, a header is attachedto the data over the index-divided track “n” to create an audio datafile accommodating a piece of music M32. The header is then erased fromthe audio data file of the track “n+1” carrying another piece of musicM41, and the audio data of the track “n+1” with the music title M41 isconnected to the audio data file of the music title M32. The two piecesof music M32 and M41 are thus combined into a single piece of music M51on one track.

The processes above are implemented by two functions. One functioninvolves adding a header to each of index-divided tracks, encryptingtrack data using a different encryption key for each track, andtransforming indexed audio data into a single audio data file. The otherfunction involves erasing header information from a given audio datafile and connecting the data in that file to another audio data file.

8. Operation During Connection With the Personal Computer

The next-generation MD1 and MD2 systems adopt the FAT system as theirdata management system in order to secure compatibility with personalcomputers. It follows that next-generation MD1 and MD2 discs are used torecord and reproduce not only audio data but also general data handledby personal computers.

On the disc drive unit 1, audio data are reproduced as they are beingread from the disc 90. When the ability of the portable-type disc driveunit 1 to access data is taken into account, audio data shouldpreferably be recorded sequentially on the disc. By contrast, thepersonal computer has no consideration for such data continuity whenwriting data to the disc; the PC records data to any free areas foundavailable on the disc.

The recording/reproducing apparatus of the invention has the personalcomputer 100 connected to the disc drive unit 1 through the USB hub 7 sothat the personal computer 100 may write data to the disc 90 loaded inthe disc drive unit 1. In that setup, general data are written undercontrol of the file system of the personal computer 100, while audiodata are written under control of the file system of the disc drive unit1.

FIGS. 52A and 52B are explanatory views sketching how managementauthority is moved between the personal computer 100 and the disc driveunit 1 connected therewith through the USB hub 7, not shown, dependingon the type of data to be written to the disc loaded in the drive unit1. FIG. 52A shows how general data are transferred from the personalcomputer 100 to the disc drive unit 1 for recording onto the disc 90 inthe drive unit 1. In this case, the file system on the part of thepersonal computer 100 provides FAT management over the disc 900.

It is assumed that the disc 90 has been formatted by either thenext-generation MD1 system or the next-generation MD2 system.

Viewed from the personal computer 100, the connected disc drive unit 1functions apparently as a removable disc under PC control. The personalcomputer 100 can then write and read data to and from the disc 90 in thedisc drive unit 1 in the same manner that the PC writes and reads datato and from a flexible disc.

The file system of the personal computer 100 may be furnished as part ofthe capabilities of an OS (Operating System) carried by the PC 100. Asis well known, the OS may be recorded as suitable program files on ahard disc drive incorporated in the personal computer 100. Uponstart-up, the program files are read and executed by the personalcomputer 100 to implement the OS capabilities.

FIG. 52B shows how audio data are transferred from the personal computer100 to the disc drive unit 1 for recording onto the disc 90 loaded inthe drive unit 1. The audio data are retrieved illustratively from thehard disc drive (HDD) held by the personal computer 100.

It is assumed that the personal computer 100 carries utility softwarefor submitting audio data to ATRAC compression encoding and forrequiring the disc drive unit 1 to write or erase audio data to or fromthe disc 90 loaded in the unit 1. The utility software is also assumedto be capable of referencing a track index file on the disc 90 in thedisc drive unit 1 in order to look up track information recorded on thedisc 90. This utility software is held illustratively as program fileson the HDD of the personal computer 100.

Described below is how audio data recorded on a storage medium of thepersonal computer 100 are typically transferred and recorded to the disc90 loaded in the disc drive unit 1. It is assumed that the utilitysoftware mentioned above is booted in advance.

The user first performs an operation on the personal computer 100causing it to write desired audio data (called the audio data Ahereunder) from its HDD to the disc 90 loaded in the disc drive unit 1.The operation triggers the utility software to issue a write requestcommand requesting a write operation of the audio data A onto the disc90. The write request command is sent from the personal computer 100 tothe disc drive unit 1.

The audio data A are then read from the HDD of the personal computer100. The retrieved audio data A are subjected to an ATRAC compressionencoding process by the utility software carried by the personalcomputer 100. The process turns the audio data A into ATRAC-compresseddata that are transferred from the personal computer 100 to the discdrive unit 1.

Upon receipt of the write request command from the personal computer100, the disc drive unit 1 starts receiving the ATRAC-compressed audiodata A being transferred from the personal computer 100. The disc driveunit 1 recognizes the command as a directive for writing the transferreddata to the disc 90 as audio data.

More specifically, the disc drive unit 1 receives the audio data A fromthe personal computer 100 through the USB hub 7. The received data areforwarded to the media drive unit 2 via the USB interface 6 and memorytransfer controller 3. With the audio data A fed to the media drive unit2, the system controller 9 causes the media drive unit 2 to write theaudio data A to the disc 90 under control of the FAT-based managementscheme of the disc drive unit 1. That is, the audio data A are writtento the disc 90 consecutively in increments of four recording blocks (64kilobytes×4) based on the FAT system of the disc drive unit 1.

Until the data write operation on the disc 90 is complete, there occurexchanges of data, status information, and commands between the personalcomputer 100 and the disc drive unit 1 in keeping with a suitableprotocol. The exchanges are performed to control the data transfer ratein such a manner that neither overflow nor underflow will occur in thecluster buffer 4.

In addition to the write request command mentioned above, an eraserequest command may be utilized by the personal computer 100. The eraserequest command is used to request the disc drive unit 1 to erase audiodata from the disc 90 loaded in the unit 1.

For example, when the personal computer 100 is connected to the discdrive unit 1 and the disc 90 is loaded in the unit 1, the utilitysoftware reads the track index file from the disc 90. The retrieved dataare transferred from the disc drive unit 1 to the personal computer 100.Based on the received data, the personal computer 100 may illustrativelydisplay a title list of the audio data held on the disc 90.

Suppose that the user at the personal computer 100 views the displayedtitle list and performs an operation to erase certain audio data (calledthe audio data B hereunder). In that case, information designating theaudio data B to be erased is transmitted to the disc drive unit 1together with an erase request command. Given the erase request command,the disc drive unit 1 under its own control erases the audio data B fromthe disc 90 as requested.

Because audio data erasure is executed by the disc drive unit 1 undercontrol of its own FAT system, it is possible to erase audio data from,say, a huge file combining a plurality of audio data files as explainedabove with reference to FIGS. 39A and 39B.

9. Restrictions on Copying of Audio Data From the Disc

Protecting the copyrights of audio data recorded on the disc 90 requiresestablishing appropriate restrictions on their copying to other storagemedia. Consider a case in which audio data held on the disc 90 aretransferred from the disc drive unit 1 to the personal computer 100 forrecording illustratively onto the HDD in the PC.

It is assumed here that the disc 90 has been formatted by either thenext-generation MD1 system or the next-generation MD2 system. It is alsoassumed that the operations such as check-in and check-out, to bediscussed below, are performed under control of the above-mentionedutility software carried by the personal computer 100.

Audio data 200 retained on the disc 90 are first moved to the personalcomputer 100 as shown in FIG. 53A. The “move” operation represents aseries of actions including the copying of the target audio data 200 tothe personal computer 100 and erasure of the audio data in question fromthe original storage medium (i.e., disc 90). That is, the move operationinvolves deleting the target data from their source location and movingthe data to their new destination.

A check-out is defined here as the operation of copying data from onestorage medium to another, with a rightful copy count (i.e., the numberof times source data are allowed to be copied legitimately) decrementedby one for the data in question. A check-in is defined as the operationof erasing checked-out data from the checkout destination, with therightful copy count for the checked-out original data incremented byone.

When the audio data 200 are moved to the personal computer 100, the dataare sent (as audio data 200′) to the storage medium such as the HDD ofthe personal computer 100 for recording thereto, and the audio data 200are erased from the disc 90. The personal computer 100 then sets anallowable (or some predetermined) checkout (CO) count 201 for the movedaudio data 200′ as shown in FIG. 53B. In this example, the allowablecheck-out count is set for “3” as indicated by three filled-in circlesin the figure. The audio data 200′ are allowed to be checked out fromthe personal computer 100 to an external storage medium as many times asthe allowable check-out count thus established.

If the checked-out audio data 200 remained erased from the original disc90, it would be inconvenient for the user. The possible inconvenience isredressed when the audio data 200′ checked out to the personal computer100 are written back to the disc 90.

When the audio data 200′ are written back to the original disc 90 fromthe personal computer 100, the allowable check-out count is decrementedby one (3−1=2) as shown in FIG. 53C. At this point, the audio data 200′held in the personal computer 100 can still be checked out rightfullytwice and thus will not be erased from the PC 100. As a result, theaudio data 200′ are copied from the personal computer 100 to the disc 90and held there as audio data 200″.

The allowable check-out count 201 is managed by use of the copyrightmanagement information contained in the track descriptors in the trackinformation table (see FIG. 34B). Because each track is assigned its owntrack descriptor, the allowable check-out count can be set for eachtrack (each piece of audio data). A track descriptor copied from thedisc 90 to the personal computer 100 is used as control information formanaging the corresponding audio data moved into the PC 100.

Illustratively, when any audio data are moved from the disc 90 to thepersonal computer 100, the track descriptor corresponding to the movedaudio data is copied to the PC 100. The personal computer 100 utilizesthe copied track descriptor in managing the audio data moved from thedisc 90. When the moved audio data are recorded to, say, the HDD of thepersonal computer 100, a predetermined allowable check-out count 201(“3” in this example) is set to the copyright management information inthe track descriptor.

In addition to the allowable check-out count, the copyright managementinformation includes an equipment ID for identifying the check-outsource device and a content ID for identifying the checked-out content(i.e., audio data). In the setup of FIG. 53C, the equipment ID of thecopy destination device is verified based on the equipment ID in thecopyright management information corresponding to the audio data to becopied. If the equipment ID in the copyright management information doesnot match the equipment ID of the copy destination device, copying isnot permitted.

In the check-out processes of FIGS. 53A through 53C, the audio data heldon the disc 90 are moved to the personal computer 100 and then writtenback to the disc 90. The procedure appears complicated from the user'sviewpoint and could be perceived as a waste of time because of the timesinvolved in reading the audio data from the disc 90 and writing the samedata back to the disc 90. Furthermore, the user would find it aberrantfor the audio data to be erased, even temporarily, from the disc 90.

Such awkwardness is avoided by skipping some of the above steps upon acheck-out of audio data from the disc 90, so that the outcome in FIG.53C is reached in more simplified fashion. Explained below is one suchsimplified procedure executed in response to a single command from theuser, such as “Check out audio data named XX from the disc 90.”

(1) The target audio data are copied from the disc 90 to the HDD of thepersonal computer 100, and the audio data recorded on the disc 90 areerased by disabling part of the management data about the audio data inquestion. For example, a link information item TINFn linked to the trackdescriptor corresponding to the audio data is erased from the play ordertable, and a link information item PINFn linked to the track descriptorcorresponding to the audio data is deleted from the programmed fileorder table. Alternatively, the track descriptors themselvescorresponding to the audio data in question may be erased. This steprenders the audio data unusable of the disc 90, after moving the datafrom the disc 90 to the personal computer 100.

(2) When the audio data are copied to the personal computer 100 in step(1) above, the track descriptors corresponding to the audio data arealso copied to the HDD of the PC 100.

(3) The personal computer 100 records a predetermined allowablecheck-out count (e.g., three times) to the copyright managementinformation in the track descriptors corresponding to the audio datacopied (i.e., moved) from the disc 90.

(4) Based on the track descriptors copied from the disc 90, the personalcomputer 100 acquires a content ID corresponding to the moved audiodata. This content ID is recorded as indicative of the audio data thatmay be checked in subsequently.

(5) The personal computer 100 then decrements by one the allowablecheck-out count recorded in step (3) above to the copyright managementinformation in the track descriptors corresponding to the moved audiodata. In this example, the allowable check-out count is now reduced to“2” (=3−1).

(6) On the disc drive unit 1, not shown, in which the disc 90 is loaded,the track descriptors corresponding to the moved audio data are enabled.This is accomplished illustratively by restoring or reconstituting thelink information items TINFn and PINFn erased in step (1) above. Wherethe track descriptors themselves corresponding to the audio data wereerased earlier, these track descriptors are reconstituted.Alternatively, the corresponding track descriptors may be transferredfrom the personal computer 100 to the disc drive unit 1 for recordingonto the disc 90.

Carrying out steps (1) through (6) above completes the entire check-outprocedure. The steps permit copying of desired audio data from the disc90 to the personal computer 100 while sparing the user redundant choresand ensuring copyright protection for the audio data in question.

The audio data copying steps (1) through (6) above are appliedpreferably to the audio data that were recorded onto the disc 90 by theuser operating the disc drive unit 1.

Checked-out audio data are checked in as follows: the personal computer100 first searches for the desired data from among the audio datarecorded therein, as well as for control information such as copyrightmanagement information in the corresponding track descriptors. With theaudio data and the control information found and ascertained, the targetdata are checked in accordingly.

10. Coexistence of the Next-Generation MD1 system With the Current MDSystem

The next-generation MD1 system can use the same disc adopted by thecurrent MD system, even thought the disc format of the next-generationMD1 system differs significantly from the disc format of the current MDsystem. This necessitates making arrangements that will keep the userfrom getting confused when using either of the two disc formats on thesame disc drive unit 1.

FIG. 54 is a schematic view portraying conceptually how thenext-generation MD1 system and the current MD system may coexist in thedisc drive unit 1. The disc drive unit 1 complies with both digital andanalog formats for the audio signal to be input and output.

Given a digital audio signal, a next-generation MD1 system 70 in FIG. 54detects a watermark from the signal by a predetermined method, gets anencryption unit 72 to encrypt the signal using key information 74, andfeeds the encrypted signal to a recording/reproduction unit 73. If ananalog audio signal is supplied, the MD1 system 70 gets an A/Dconverter, not shown, to covert the signal into a digital audio datasignal, detects a watermark from the audio data signal, encrypts thesignal, and sends the encrypted signal to the recording/reproductionunit 73. The recording/reproduction unit 73 subjects the encrypted audiodata to ATRAC compression encoding. The compression-coded audio data areconverted to 1-7 pp modulation format together with the key information74 before getting recorded to the disc 90, not shown.

If the watermark detected from the input audio signal containsillustratively copy guard information, then the recording/reproductionunit 73 may be inhibited from carrying out any write operationaccordingly.

For audio data reproduction, both the audio data and the correspondingkey information 74 are read from the disc 90 by therecording/reproduction unit 73. The data are decrypted by a decryptionunit 75 using the key information 74, whereby a digital audio signal isacquired. The digital audio signal thus obtained is converted to ananalog audio signal by a D/A converter, not shown, for output.Alternatively, the digital audio signal may be output unconvertedwithout the intervention of the D/A converter. A watermark may also bedetected from the audio signal being reproduced from the disc 90.

If the detected watermark is judged to include copy guard information,the recording/reproduction unit 73 may be inhibited from carrying outaudio data reproduction accordingly.

In a current MD system 71 of FIG. 54, a digital audio signal isfurnished with generation management information by SCMS (Serial CopyManagement System) before being forwarded to a recording/reproductionunit 76. An analog audio signal, if supplied, is converted to digitalaudio data by an A/D converter, not shown, before being fed to therecording/reproduction unit 76. The analog audio signal is not furnishedwith generation management information by SCMS. Therecording/reproduction unit 76 submits the received audio data to ATRACcompression encoding. The compression-coded audio data are converted toEFM format before being written to the disc 90, not shown.

For audio data reproduction, the desired audio data are read as adigital audio signal from the disc 90 by the recording/reproduction unit76. The digital audio signal is converted to an analog audio signal bythe D/A converter, not shown, for output. Alternatively, the digitalaudio signal may be output unconverted without the intervention of theD/A converter.

In the above-described disc drive unit 1 in which the next-generationMD1 system and the current MD system coexist, a switch 50 is provided toswitch explicitly between the operation modes of the two MD systems. Inparticular, the switch 50 is used effectively when audio data are to berecorded to the disc 90.

FIG. 55 is an external view of a portable-type disc drive unit 1. Thedisc drive unit 1 is equipped with a hinge, which is located in the rearand hidden in FIG. 55. Sliding on a slider 52 allows a lid 54 around thehinge to swing open away from a body 55. A disc guide appears in theopening through which to insert the disc 90. When the disc 90 isinserted along the guide and the lid 54 is swung shut, the disc 90 isloaded into the disc drive unit 1. With the disc 90 thus loaded, thedisc drive unit 1 automatically reads information from the lead-in areaand U-TOC area of the disc 90.

A phone jack 53 serves as an analog audio signal output terminal. Theuser may plug audio reproduction means such as headphones into the phonejack 53 to enjoy the sound of audio data reproduced from the disc 90.

Although not shown in FIG. 55, the disc drive unit 1 is also providedwith various keys for control purposes: keys for designating discoperations such as play, record, stop, pause, fast forward, and rewind;keys for editing the audio data and other information held on the disc90; and keys for inputting commands and data into the disc drive unit 1.These keys are located illustratively on the body 55.

The above-mentioned switch 50 is attached illustratively to the lid 54of the disc drive unit 1. As shown in FIG. 55, the switch 50 is madefairly large in size and located conspicuously to attract the user'sattention. On the disc drive unit 1 in FIG. 55, the switch 50 is shownswitchable either to “MD” for the operation mode of the current MDsystem or to “NEXT-GENERATION MD” for the operation mode of thenext-generation MD1 system .

The lid 54 is also equipped with a display unit 51. The display unit 51displays various operation states of the disc drive unit 1 and trackinformation from the disc 90 loaded in the unit 1. The display unit 51also gives onscreen indications in conjunction with the operation modeset by use of the switch 50.

Described below with reference to the flowchart of FIG. 56 is how thedisc drive unit 1 typically works when formatting the disc 90. The stepsin FIG. 56 apply when a so-called virgin disc (unused disc) is to beformatted. In the first step S200 of FIG. 56, a current MD system disc90 is loaded into the disc drive unit 1. With the disc 90 loaded, stepS201 is reached in which information is read first from the lead-in areaand then from the U-TOC area on the disc 90.

In step S202, a check is made to see whether the operation mode of thedisc drive unit 1 is set by the switch 50 for the current MD system orfor the next-generation MD1 system . If in step S202 the operation modeis judged set for the current MD system, step S203 is reached. In stepS203, the loaded disc 90 is judged usable as a current MD system discwith no need for further formatting, which is characteristic of thecurrent MD system. The display unit 51 then gives an onscreen indicationsaying that the disc 90 is a blank disc.

If in step S202 the operation mode of the disc drive unit 1 is judgedset for the next-generation MD1 system, then step S204 is reached. Instep S204, the display unit 51 indicates that the disc 90 is a blankdisc for a period of, say, several seconds before step S205 is reachedautomatically.

In step S205, the display unit 51 is made to display a message askingthe user whether or not to proceed with formatting of the disc 90. Ifthe user gives an instruction specifying that the disc 90 is to beformatted, step S206 is reached. Illustratively, the instruction isentered into the disc drive unit 1 by the user operating a suitable keyon the body 55 of the unit 1.

In step S206, the disc drive unit 1 submits the disc 90 to a formattingprocess of the next-generation MD1 system in the manner describedearlier with reference to the flowchart of FIG. 18. While the disc 90 isbeing formatted, the display unit 51 should preferably indicate theformatting process is in progress. With the formatting process completedin step S206, step S207 is reached. In step S207, the display unit 51 ismade to give a message saying that the loaded disc 90 is a blanknext-generation MD1 disc.

If in step S205 the user gives an instruction that the disc 90 is not tobe formatted, step S205 is followed by step S208. In step S208, thedisplay unit 51 gives an indication prompting the user to set the switch50 for the operation mode of the current MD system in the disc driveunit 1. In step S209, a check is made, upon elapse of a predeterminedperiod of time, to see whether the setting of the switch 50 staysunchanged despite the indication on the display unit 51. If the settingof the switch 50 is judged unchanged in step S209, a time-out isrecognized and control is returned to step S205.

FIG. 57 is another flowchart of steps carried out by the disc drive unit1 in formatting a virgin disc 90 loaded therein. In step S300 of FIG.57, a blank (unused) disc 90 is loaded into the disc drive unit 1. Instep S301, information is read first from the lead-in area and then fromthe U-TOC area of the disc 90. In step S302, based on the U-TOCinformation thus acquired, the display unit 51 is made to give anindication that the loaded disc 90 is a blank disc.

In step S303, the record key (not shown) on the disc drive unit 1 isoperated to instruct that data are to be recorded to the disc 90 in thedisc drive unit 1. The recording instruction may be given to the discdrive unit 1 not only by operation of the record key of the unit 1 butalso from, say, the personal computer 100 connected to the disc driveunit 1.

With the recording instruction given to the disc drive unit 1 in stepS303, step S304 is reached. In step S304, a check is made to see whetherthe operation mode of the disc drive unit 1 is set by the switch 50 forthe next-generation MD1 system or for the current MD system. If in stepS304 the operation mode of the disc drive unit 1 is judged set for thecurrent MD system, then step S306 is reached. In step S306, a recordingprocess of the current MD system is started on the disc 90.

If in step S304 the operation mode of the disc drive unit 1 is judgedset for the next-generation MD1 system by the switch 50, step S305 isreached. In step S305, the disc 90 is formatted by the next-generationMD1 system in the manner described earlier with reference to FIG. 18.Step S305 is followed by step S306 in which a recording process of thenext-generation MD1 system is started on the formatted disc 90.

Described below with reference to the flowchart of FIG. 58 is how thedisc drive unit 1 typically works when recording audio data to the disc90. The processing varies depending on whether the operation mode of thedisc drive unit 1 matches the type of the disc 90, i.e., whether thedisc 90 has been formatted by the next-generation MD1 system .

In the first step S210 of FIG. 58, the disc 90 is loaded into the discdrive unit 1. With the disc 90 loaded, step S211 is reached in whichinformation is read first from the lead-in area and then from the U-TOCarea of the disc 90.

Based on the U-TOC information thus retrieved, a check is made in stepS212 to determine whether the loaded disc 90 has the format of thenext-generation MD1 system or the format of the current MD system. Thecheck is made illustratively on the basis of whether FAT data have beenretrieved from the U-TOC area. Alternatively, the check may be carriedout based on whether alert track start location information is found inthe U-TOC area.

In step S213, the display unit 51 is made to indicate the disc typedetermined in step S212. In step S214, the status of the loaded disc 90is displayed on the display unit 51 in accordance with the informationread from the U-TOC area. Illustratively, the display indicates whetherthe loaded disc 90 is a blank disc. If the disc 90 is not a blank disc,the disc name and track name information are displayed. In step S215,the rotation of the disc 90 is stopped.

In step S216, a check is made to see if the disc type determined in stepS212 matches the operation mode of the disc drive unit 1 set by theswitch 50. In case of a match, step S217 is reached.

More specifically, step S217 is reached in one of two cases: where theswitch 50 is judged set for the operation mode of the current MD systemand the loaded disc 90 turns out to be a current MD system disc on theone hand; and where the switch 50 is judged set for the operation modeof the next-generation MD1 system and the loaded disc 90 is found tohave the format of the next-generation MD1 system on the other hand.

In step S217, data may be recorded to or reproduced from the disc 90. Itis also possible to edit information in the U-TOC area on the disc 90.

At this point, depending on the disc type determined in step S212, thesystem controller 9 causes the media drive unit 2 to select using theselector 26 an appropriate signal path complying with the modulationsystem for the disc type in effect. This makes it possible to switch thedemodulation formats automatically between the next-generation MD1system and the current MD system for audio data reproduction. The filesystems are also switched in like manner between the next-generation MD1system and the current MD system under control of the system controller9 based on the disc type in effect.

It might happen in step S216 that the disc type determined in step S212does not match the operation mode of the disc drive unit 1 set by theswitch 50. In that case, step S216 is followed by step S219.

More specifically, step S219 is reached in one of two cases: where theswitch 50 is judged set for the operation mode of the current MD systemand the loaded disc 90 turns out to have the format of thenext-generation MD1 system on the one hand; and where the switch 50 isjudged set for the operation mode of the next-generation MD1 system andthe loaded disc 90 is found to have the format of the current MD systemon the other hand.

In step S219, a check is made to see what operation is carried out bythe user on the disc 90. If in step S219 the user is judged to haveperformed an operation to reproduce (“PB”) audio data from the disc 90,then step S220 is reached. In step S220, the audio data are reproducedfrom the disc 90 as instructed by the user.

That is, even if the disc type does not match the operation mode of thedisc drive unit 1 set by the switch 50, the audio data recorded on thedisc 90 can be reproduced regardless of the setting of the switch 50.

More specifically, depending on the disc type determined in step S212,the system controller 9 causes the media drive unit 2 to select usingthe selector 26 an appropriate signal path complying with the modulationsystem for the disc type in effect. This makes it possible to switch thedemodulation formats automatically between the next-generation MD1system and the current MD system for audio data reproduction. The filesystems are also switched in like manner between the next-generation MD1system and the current MD system under control of the system controller9 based on the disc type in effect.

If in step S219 the user is judged to have performed an operation torecord (“REC”) audio data to the disc 90 or to erase or otherwise edit(“EDIT”) recorded audio data on the disc 90, then step S218 is reached.In step S218, a warning message appears on the display unit 51 sayingthat the type of the disc 90 does not match the operation mode of thedisc drive unit 1. Also displayed is a message saying that recording isnot available if the user has designated recording, or that editing isimpossible if the user has specified editing.

If in step S219 the user attempts to update the U-TOC area in an editingoperation during audio data reproduction, the display unit 51 displaystwo messages: that the type of-the disc 90 does not match the operationmode of the disc drive unit 1, and that editing is not available at thisstage.

That is, where the disc type does not comply with the operation mode ofthe disc drive unit 1 set by the switch 50, no operation, which wouldmodify information recorded on the disc 90, is permitted.

How the disc 90 is changed in its format will now be described. On thedisc 90, it is possible to change the format of the next-generation MD1system into the format of the current MD system and vice versa.

FIG. 59 is a flowchart of steps for switching from the disc format ofthe next-generation MD1 system to the disc format of the current MDsystem on the disc 90. It is assumed here that the switch 50 is set inadvance for the operation mode of the next-generation MD1 system .

In the first step S230 of FIG. 59, the disc 90 is loaded into the discdrive unit 1. With the disc 90 loaded, step S231 is reached in whichinformation is read first from the lead-in area and then from the U-TOCarea of the disc 90. In step S232, it is recognized that the loaded disc90 has been formatted by the next-generation MD1 system . In step S233,the rotation of the disc 90 is stopped.

In step S234, all data recorded and managed by the FAT system are erasedfrom the disc 90. For example, the user performs an operation to editdata (“EDIT”) recorded under the FAT management scheme on the disc 90,and selects from among editing alternatives an operation to erase alldata (“ALL ERASE”). It is preferred in step S234 that an indication begiven on the display unit 51 asking the user to confirm his or herintention to actually erase all data from the disc 90.

After all data recorded under the FAT management scheme are erased fromthe disc 90 according to the user's operation, step S235 is reached. Instep S235, a message saying that the loaded disc has now become a blankdisc appears on the display unit 51.

Step S235 is followed by step S236 in which the user operates the switch50 to set the operation mode of the disc drive unit 1 for the current MDsystem. In step S237, information is read from the U-TOC area of theloaded disc 90. In step S238, the disc 90 is recognized as a discformatted by the next-generation MD1 system .

In step S239, a message saying that the loaded disc is a blanknext-generation MD1 system disc on the display unit 51. An indicationalso appears on the display unit 51 asking the user whether or not tocancel the format of the next-generation MD1 system . Canceling theformat of the next-generation MD1 system means switching from the discformat of the next-generation MD1 system to the disc format of thecurrent MD system on the loaded disc 90.

If in step S239 the user is judged to have an operation to cancel thedisc format, step S240 is reached. In step S240, the format of thenext-generation MD1 system on the loaded disc 90 is canceled.Illustratively, the disc format is canceled erasing the FAT informationfrom the T-TOC area as well as the alert track. Alternatively, thenext-generation MD1 system format may be canceled by erasing not the FATinformation but the alert track alone.

If in step S239 the user is judged to have performed an operation not tocancel the disc format, step S241 is reached. In step S241, anindication appears on the display unit 51 prompting the user to operatethe switch 50 to set the disc drive unit 1 for the operation mode of thenext-generation MD1 system .

In step S242, a check is made to see whether the user carries out theoperation to set the disc drive unit 1 for the operation mode of thenext-generation MD1 system within a predetermined period of time. If therelevant operation is judged performed within the predetermined timeperiod, then step S243 is reached in which the processing is terminatedand the loaded disc 90 is rendered usable as a blank disc formatted bythe next-generation MD1 system . If in step S242 the setting of theswitch 50 is not completed within the predetermined time period, atime-out is recognized and control is returned to step S239.

Switching from the disc format of the current MD system to the discformat of the next-generation MD1 system is performed as follows: theswitch 50 is first operated to set the disc drive unit 1 for theoperation mode of the current MD system. An operation is carried out toerase from the disc 90 all audio data recorded in the format of thecurrent MD system. Then the disc 90 is formatted anew by thenext-generation MD1 system in the manner discussed earlier withreference to FIG. 18.

With the above features in place, the inventive method and apparatus arecapable of managing audio data efficiently under control of the FATsystem using a storage medium whose specifications are equivalent tothose of the current MD system.

While a preferred embodiment of the invention has been described usingspecific terms, such description is for illustrative purposes only, andit is to be understood that changes and variations may be made withoutdeparting from the spirit or scope of the following claims.

The present document contains subject matter related to that disclosedin Japanese Patent Application P2002-099277, filed in the JapanesePatent Office (JPO) on Apr. 1, 2002; Japanese Patent ApplicationP2002-190812, filed in the JPO on Jun. 28, 2002; Japanese PatentApplication P2002-099294 filed in the JPO on Apr. 1, 2002; JapanesePatent Application P2002-190811 filed in the JPO on Jun. 28, 2002;Japanese Patent Application P2002-099274 filed in the JPO on Apr. 1,2002; Japanese Patent Application P2002-190804 filed in the JPO on Jun.28, 2002; Japanese Patent Application P2002-099278 filed in the JPO onApr. 1, 2002; Japanese Patent Application P2002-190805 filed Jun. 28,2002; Japanese Patent Application P2002-099276 filed in the JPO on Apr.1, 2002; Japanese Patent Application P2002-190808 filed in the JPO onJun. 28, 2002; Japanese Patent Application P2002-099296 filed in the JPOon Apr. 1, 2002; Japanese Patent Application P2002-190809 filed in theJPO on Jun. 28, 2002; Japanese Patent Application P2002-099272 filed inthe JPO on Apr. 1, 2002; Patent Application P2002-190802 filed in theJPO on Jun. 28, 2002; Japanese Patent Application P2002-099271 filed inthe JPO on Apr. 1, 2002; Japanese Patent Application P2002-190803 filedin the JPO on Jun. 28, 2002; Japanese Patent Application P2002-099270filed in the JPO on Apr. 1, 2002; Japanese Patent ApplicationP2002-190578 filed in the JPO on Jun. 28, 2002; Japanese PatentApplication P2002-099273 filed in the JPO on Apr. 1, 2002; JapanesePatent Application P2002-190810 filed in the JPO on Jun. 28, 2002;Japanese Patent Application P2002-099279 filed in the JPO on Apr. 1,2002; and Japanese Patent Application P2002-190801, filed in the JPO onJun. 28, 2002, the entire contents of each of the above-identifieddocuments being incorporated herein by reference.

1. A recording method comprising: causing a first file allocation table(FAT) management system retained in a first apparatus to manage astorage medium loaded in a second apparatus when the first apparatus andthe second apparatus are connected to one another; and recording (1)first general type data to said storage medium based on the first (FAT)management system which is retained in said first apparatus when it isdetermined that the first general type data transferred from said firstapparatus to said second apparatus are to be recorded to said storagemedium, said first general type data to be recorded non-sequentially tosaid storage medium, and (2) recording second audio type data, differentfrom the first general type data and that is to be recorded sequentiallyto said storage medium, to said storage medium based on a second fileallocation table (FAT) management system which is retained in saidsecond apparatus and which sequentially records audio data recordingsegments when it is determined that the second audio type datatransferred from said first apparatus to said second apparatus are to berecorded to said storage medium.
 2. A recording method according toclaim 1, further comprising: recording said second audio type data tosaid storage medium under said second (FAT) management system based on awrite request command transferred from said first apparatus to saidsecond apparatus.
 3. A recording method according to claim 2, furthercomprising: executing software instructions stored in a storing meanswithin said first apparatus so as to output said write request commandto record said audio data as the second audio type data stored in saidstoring means to said storage medium in response to a user-actuatedinstruction; transferring said write request command from said firstapparatus to said second apparatus; reading-out said audio data fromsaid storing means; executing other software instructions so as tocompress said audio data and output compressed audio data; transferringsaid compressed audio data from said first apparatus to said secondapparatus; and recording at said second apparatus said compressed audiodata to said storage medium under said second (FAT) management systemaccording to said write request command.
 4. A recording method accordingto claim 3, further comprising: searching for free areas having at leasta predetermined physical length based on said second (FAT) managementsystem configured to manage a file stored in said storage medium;generating a track descriptor having an attribute of a track and anencryption key configured to encrypt said compressed audio data to bestored in said storage medium; generating a part descriptor having partpointer information pointing to said file; recording as encryptedcompressed audio data said compressed audio data encrypted with saidencryption key in said free areas; connecting said free areas where saidencrypted compressed audio data is recorded to an end of said filemanaged by said second management system under said second (FAT)management system; recording the part pointer information pointing tosaid free areas where said encrypted compressed audio data is recordedin said part descriptor; recording a decryption key so as to enablelater decryption of said encrypted compressed audio data and pointerinformation pointing to said part descriptor in said track descriptor;and recording a track number that points to said track descriptor in aplay order table having a play order of a plurality of tracks.
 5. Arecording method according to claim 4, wherein said second (FAT)management system is configured to search consecutive free areas havingat least a physical length of 64 kilobytes multiplied by four.
 6. Arecording method in a recording apparatus, comprising: causing a firstfile allocation table (FAT) management system retained in a firstapparatus to manage a storage medium loaded in said recording apparatuswhen said recording apparatus and said first apparatus are connected;and recording (1) first general type data to said storage medium basedon the first (FAT) management system which is retained in said firstapparatus when the first general type data transferred from said firstapparatus to said recording apparatus are to be recorded to said storagemedium, said first general type data to be recorded non-sequentially tosaid storage medium, and (2) recording second audio type data, differentfrom the first general type data and that is to be recorded sequentiallyto said storage medium, to said storage medium based on a second fileallocation table (FAT) management system which is retained in saidrecording apparatus and which sequentially records data recordingsegments when the second audio type data transferred from said firstapparatus to said recording apparatus are to be recorded to said storagemedium.
 7. An editing method comprising: causing a first file allocationtable (FAT) management system retained in a first apparatus to manage astorage medium loaded in a second apparatus when said first apparatusand said second apparatus are connected; and deleting (1) a part of afirst general type file from said storage medium based on the first(FAT) management system which is retained in said first apparatus whensaid first apparatus instructs said part of said first general type fileto be deleted from said storage medium loaded in said second apparatus,said first general type file having been recorded non-sequentially tosaid storage medium, and (2) deleting a part of a second audio typefile, different from said first general type file and that has beenrecorded sequentially to said storage medium, based on a second fileallocation table (FAT) management system which is retained in saidsecond apparatus when said first apparatus instructs said part of saidsecond audio type file to be deleted from said storage medium loaded insaid second apparatus.
 8. An editing method according to claim 7,wherein a data management method based on said second (FAT) managementsystem comprising: obtaining track information corresponding to apredetermined track from a play order table having a plurality of trackinformation that respectively point to a track descriptor in a trackinformation table; obtaining a track descriptor designated by said trackinformation from the track information table, said track descriptorincluding a decryption key corresponding to a track and pointerinformation that points to one of a plurality of part descriptors in apart information table; reading a part descriptor corresponding to saidpointer information in said track descriptor; reading a part of saidsecond audio type file according to part pointer information in saidpart descriptor, said part pointer information pointing to said part ofsaid second audio type file; and decrypting with said decryption keysaid part of said second audio type file.
 9. An editing method accordingto claim 7, further comprising: transferring a delete request commandand a track identification to be deleted from said first apparatus tosecond apparatus; obtaining track information corresponding to saidtrack to be deleted from a play order table; obtaining a trackdescriptor designated by said track information from a track informationtable; adjusting a play order of a track set to be played after saidtrack to be deleted; reading a part descriptor corresponding to apointer information in said track descriptor; separating a data block asa part of said second audio type file specified by said pointerinformation from said part descripor from said second audio type file onsaid second (FAT) management system and freeing said data block on saidsecond (FAT) management system; freeing said part descriptor; andfreeing said track descriptor.
 10. An editing method in an editingapparatus, comprising: causing a first file allocation table (FAT)management system retained in a first apparatus to manage a storagemedium loaded in said editing apparatus when said editing apparatus andsaid first apparatus are connected to one another; and deleting (1) apart of a first general type file based on the first (FAT) managementsystem that is retained in said first apparatus when first apparatusinstructs said part of said first general type file to be deleted fromsaid storage medium loaded in said editing apparatus, said first generaltype file having been recorded non-sequentially to said storage medium,and (2) deleting a part of a second audio type file, different from saidfirst general type file and that has been recorded sequentially to saidstorage medium, based on a second file allocation table (FAT) managementsystem that is retained in said editing apparatus when said firstapparatus instructs said part of said second audio type file to bedeleted from said storage medium loaded in said editing apparatus.